View source for Ohio River

{{Short description|Major river in the midwestern United States}}
{{Redirect|Ohio Valley}}
{{Use mdy dates|date=January 2024}}
{{Infobox river
 | name                 = Ohio River
 | native_name          = {{native name|see|Ohi:yo'}}
 | name_etymology       = 
<!---------------------- IMAGE & MAP -->
 | image                = Ohio_River.jpg
 | image_size           = 300
 | image_caption        = The widest point on the Ohio River is just north of [[downtown Louisville]], where it is {{convert|1|mi|km|spell=in}} wide. [[Indiana]] is on the right towards the flood gates, [[Kentucky]] on the left, towards the locks. The jetty on the left is the entrance to the [[Louisville and Portland Canal]].
 | map                  = Ohiorivermap.png
 | map_size             = 300
 | map_caption          = Ohio River basin
 | pushpin_map          = 
 | pushpin_map_size     = 300
 | pushpin_map_caption  = 
<!---------------------- LOCATION -->
 | subdivision_type1    = Country
 | subdivision_name1    = [[United States]]
 | subdivision_type2    = States
 | subdivision_name2    = [[Pennsylvania]], [[Ohio]], [[West Virginia]], [[Kentucky]], [[Indiana]], [[Illinois]]
 | subdivision_type3    = 
 | subdivision_name3    = 
 | subdivision_type4    = 
 | subdivision_name4    = 
 | subdivision_type5    = Cities
 | subdivision_name5    = [[Pittsburgh, PA]]; [[East Liverpool, OH]]; [[Steubenville, OH]]; [[Wheeling, WV]]; [[Parkersburg, WV]]; [[Huntington, WV]]; [[Ashland, KY]]; [[Portsmouth, OH]]; [[Cincinnati, OH]]; [[Louisville, KY]]; [[Owensboro, KY]]; [[Evansville, IN]]; [[Henderson, KY]]; [[Mount Vernon, IN]]; [[Paducah, KY]]; [[Cairo, IL]]
<!---------------------- PHYSICAL CHARACTERISTICS -->
 | length               = {{convert|981|mi|km|abbr=on}} 
 | width_min            = 
 | width_avg            = 
 | width_max            = 
 | depth_min            = 
 | depth_avg            = 
 | depth_max            = 
 | discharge1_location  = [[Cairo, Illinois|Cairo]]<ref name=Leeden1990>{{cite book |first1=Frits van der |last1=Leeden |first2=Fred L. |last2=Troise |first3=David Keith |last3=Todd |title=The Water Encyclopedia |edition=Second |page=[https://archive.org/details/waterencyclopedi0000vand/page/126 126] |location=Chelsea, Michigan |publisher=Lewis Publishers |year=1990 |isbn=978-0-87371-120-3 |url=https://archive.org/details/waterencyclopedi0000vand/page/126}}</ref>
 | discharge2_location  = [[Olmsted, Illinois|Olmsted]]
 | discharge2_min       = {{cvt|40,300|cuft/s|m3/s|abbr=on}} (2016/10/14)<ref name="USGS 03612600 OHIO RIVER AT OLMSTED, IL">{{Cite web|url=https://waterdata.usgs.gov/nwis/annual/?referred_module=sw&site_no=03612600&por_03612600_59246=262616,00060,59246,2013,2024&year_type=W&format=html_table&date_format=YYYY-MM-DD&rdb_compression=file&submitted_form=parameter_selection_list|title=USGS Surface Water data for USA: USGS Surface-Water Annual Statistics|website=waterdata.usgs.gov|access-date=October 26, 2025|archive-date=April 14, 2025|archive-url=https://web.archive.org/web/20250414215748/https://waterdata.usgs.gov/nwis/annual/?referred_module=sw&site_no=03612600&por_03612600_59246=262616,00060,59246,2013,2024&year_type=W&format=html_table&date_format=YYYY-MM-DD&rdb_compression=file&submitted_form=parameter_selection_list|url-status=live}}</ref>
 | discharge2_avg       = (Period: 2013–2023) {{cvt|338,000|cuft/s|m3/s|abbr=on}}<ref name="USGS 03612600 OHIO RIVER AT OLMSTED, IL"/>
 | discharge2_max       = {{cvt|1,240,000|cuft/s|m3/s|abbr=on}} (2019/02/24)<ref name="USGS 03612600 OHIO RIVER AT OLMSTED, IL"/>
 | discharge3_min       = {{cvt|15,000|cuft/s|m3/s|abbr=on}} (1930/07/20)<ref name="USGS 03611500 OHIO RIVER AT METROPOLIS, IL">{{Cite web|url=https://waterdata.usgs.gov/nwis/annual?referred_module=sw&site_no=03611500&por_03611500_59236=262609,00060,59236,1928,2015&year_type=W&format=html_table&date_format=YYYY-MM-DD&rdb_compression=file&submitted_form=parameter_selection_list|title=USGS Surface Water data for USA: USGS Surface-Water Annual Statistics|website=waterdata.usgs.gov|access-date=October 26, 2025|archive-date=April 27, 2025|archive-url=https://web.archive.org/web/20250427133248/https://waterdata.usgs.gov/nwis/annual?referred_module=sw&site_no=03611500&por_03611500_59236=262609,00060,59236,1928,2015&year_type=W&format=html_table&date_format=YYYY-MM-DD&rdb_compression=file&submitted_form=parameter_selection_list|url-status=live}}</ref><ref name="03611500 OHIO RIVER AT METROPOLIS, IL">{{cite web|url=https://waterdata.usgs.gov/nwis/wys_rpt?dv_ts_ids=59236&wys_water_yr=2014&site_no=03611500&agency_cd=USGS&adr_water_years=2006%2C2007%2C2008%2C2009%2C2010%2C2011%2C2012%2C2013%2C2014%2C2015&referred_module=|title=03611500 OHIO RIVER AT METROPOLIS, IL|website=waterdata.usgs.gov|access-date=August 2, 2024|archive-date=November 30, 2024|archive-url=https://web.archive.org/web/20241130060724/https://waterdata.usgs.gov/nwis/wys_rpt?dv_ts_ids=59236&wys_water_yr=2014&site_no=03611500&agency_cd=USGS&adr_water_years=2006,2007,2008,2009,2010,2011,2012,2013,2014,2015&referred_module=|url-status=live}}</ref>
 | discharge1_avg       = (Period: 1951–1980) {{cvt|281,000|cuft/s|m3/s|abbr=on}}<ref name=Leeden1990 />
 | discharge3_max       = {{cvt|1,850,000|cuft/s|m3/s|abbr=on}} (1937/02/01)<ref name="USGS 03611500 OHIO RIVER AT METROPOLIS, IL"/><ref name="03611500 OHIO RIVER AT METROPOLIS, IL"/>
 | discharge3_location  = [[Metropolis, Illinois|Metropolis]]
 | discharge3_avg      =(Period: 1928–2014) {{cvt|279,100|cuft/s|m3/s|abbr=on}}<ref name="03611500 OHIO RIVER AT METROPOLIS, IL"/>
 | discharge5_location  = [[Greater Pittsburgh|Pittsburgh]]
 | discharge5_avg     =(Period: 1934–2023) {{cvt|34,020|cuft/s|m3/s|abbr=on}}<ref name="03086000 OHIO RIVER AT SEWICKLEY, PA">{{cite web|url=https://waterdata.usgs.gov/nwis/wys_rpt?dv_ts_ids=120279&wys_water_yr=2023&site_no=03086000&agency_cd=USGS&adr_water_years=2006%2C2007%2C2008%2C2009%2C2010%2C2011%2C2012%2C2013%2C2014%2C2015%2C2016%2C2017%2C2018%2C2019%2C2020%2C2021%2C2022%2C2023&referred_module=|title=03086000 OHIO RIVER AT SEWICKLEY, PA|website=waterdata.usgs.gov|access-date=August 2, 2024|archive-date=April 15, 2025|archive-url=https://web.archive.org/web/20250415220056/https://waterdata.usgs.gov/nwis/wys_rpt?dv_ts_ids=120279&wys_water_yr=2023&site_no=03086000&agency_cd=USGS&adr_water_years=2006%2C2007%2C2008%2C2009%2C2010%2C2011%2C2012%2C2013%2C2014%2C2015%2C2016%2C2017%2C2018%2C2019%2C2020%2C2021%2C2022%2C2023&referred_module=|url-status=live}}</ref>
 | discharge5_min     ={{cvt|2,100|cuft/s|m3/s|abbr=on}} (1957/09/04)<ref name="03086000 OHIO RIVER AT SEWICKLEY, PA"/>
 | discharge5_max    ={{cvt|574,000|cuft/s|m3/s|abbr=on}} (1936/03/18)<ref name="03086000 OHIO RIVER AT SEWICKLEY, PA"/>
 | discharge4_location  = [[Louisville, Kentucky|Louisville]]
 | discharge4_min     ={{cvt|877|cuft/s|m3/s|abbr=on}} (2010/09/21)<ref name="03294500 OHIO RIVER AT LOUISVILLE, KY">{{cite web|url=https://waterdata.usgs.gov/nwis/wys_rpt?dv_ts_ids=58871&wys_water_yr=2020&site_no=03294500&agency_cd=USGS&adr_water_years=2006%2C2007%2C2008%2C2009%2C2010%2C2011%2C2012%2C2013%2C2014%2C2015%2C2016%2C2017%2C2018%2C2019%2C2020&referred_module=|title=03294500 OHIO RIVER AT LOUISVILLE, KY|website=waterdata.usgs.gov|access-date=August 2, 2024|archive-date=April 16, 2025|archive-url=https://web.archive.org/web/20250416042119/https://waterdata.usgs.gov/nwis/wys_rpt?dv_ts_ids=58871&wys_water_yr=2020&site_no=03294500&agency_cd=USGS&adr_water_years=2006%2C2007%2C2008%2C2009%2C2010%2C2011%2C2012%2C2013%2C2014%2C2015%2C2016%2C2017%2C2018%2C2019%2C2020&referred_module=|url-status=live}}</ref>
 | discharge4_avg     =(Period: 1929–2020) {{cvt|120,800|cuft/s|m3/s|abbr=on}}<ref name="03294500 OHIO RIVER AT LOUISVILLE, KY"/>
 | discharge4_max     ={{cvt|1,110,000|cuft/s|m3/s|abbr=on}} (1937/01/27)<ref name="03294500 OHIO RIVER AT LOUISVILLE, KY"/>
<!---------------------- BASIN FEATURES -->
 | source1              = [[Allegheny River]]
 | source1_location     = [[Allegany Township, Pennsylvania]]
 | source1_coordinates  = {{coord|41|52|22|N|77|52|30|W|region:US-PA_type:river|display=inline}}
 | source1_elevation    = {{convert|2240|ft|abbr=on}}
 | source2              = [[Monongahela River]] 
 | source2_location     = [[Fairmont, West Virginia]]
 | source2_coordinates  = {{coord|39|27|53|N|80|09|13|W|region:US-WV_type:river|display=inline}}
 | source2_elevation    = {{convert|880|ft|abbr=on}}
 | source_confluence    = 
 | source_confluence_location    = [[Pittsburgh]], Pennsylvania
 | source_confluence_coordinates= {{coord|40|26|32|N|80|00|52|W|region:US-PA_type:river|display=inline}}
 | source_confluence_elevation   = {{convert|730|ft|abbr=on}}
 | mouth                = [[Mississippi River]]
 | mouth_location       = at [[Cairo, Illinois]] / [[Ballard County, Kentucky]]
 | mouth_coordinates    = {{coord|36|59|12|N|89|07|50|W|region:US-IL_type:river|display=inline,title}}
 | mouth_elevation      = {{convert|290|ft|abbr=on}}
 | progression          = [[Mississippi River]] → [[Gulf of Mexico]] 
 | river_system         = 
 | basin_size           = {{cvt|203,940|mi2|km2|abbr=on}}<ref name="Ohio River Basin">{{Cite web|url=https://www.usgs.gov/centers/ohio-kentucky-indiana-water-science-center/science/science-topics/ohio-river-basin|title=Ohio River Basin &#124; U.S. Geological Survey|date=September 3, 2020|website=www.usgs.gov}}</ref>
 | tributaries_left     = [[Little Kanawha River]], [[Kanawha River]], [[Guyandotte River]], [[Big Sandy River (Ohio River)|Big Sandy River]], [[Little Sandy River (Kentucky)|Little Sandy River]], [[Licking River (Kentucky)|Licking River]], [[Kentucky River]], [[Salt River (Kentucky)|Salt River]], [[Green River (Kentucky)|Green River]], [[Cumberland River]], [[Tennessee River]]
 | tributaries_right    = [[Beaver River (Pennsylvania)|Beaver River]], [[Little Muskingum River]], [[Muskingum River]], [[Little Hocking River]], [[Hocking River]], [[Shade River]], [[Scioto River]], [[Little Miami River]], [[Great Miami River]], [[Wabash River]]
 | custom_label         = 
 | custom_data          = 
 | mapframe             = yes| mapframe-wikidata=yes| mapframe-zoom=5| mapframe-height=250| mapframe-frame-width = 300| mapframe-stroke-width=1.5
}}

The '''Ohio River''' ({{langx|see|Ohi:yo'}}) is a {{convert|981|mi|km|adj=mid|-long}} [[river]] in the [[United States]]. It is located at the boundary of the [[Midwestern]] and [[Southern United States]], flowing in a southwesterly direction from [[Pittsburgh]], Pennsylvania, to its [[river mouth|mouth]] on the [[Mississippi River]] in [[Cairo, Illinois]]. It is the third largest river by discharge volume in the United States and the largest [[tributary]] by volume of the Mississippi River.<ref>{{cite web|url=https://pubs.usgs.gov/of/1987/ofr87-242/|title=Largest Rivers in the United States|publisher=[[United States Geological Survey]]|access-date=December 13, 2019|archive-date=April 28, 2012|archive-url=https://web.archive.org/web/20120428185541/http://pubs.usgs.gov/of/1987/ofr87-242/|url-status=live}}</ref> It is also the sixth oldest river on the North American continent. The river flows through or along the border of six [[U.S. state|states]], and its [[drainage basin]] includes parts of 14 states. Through its largest tributary, the [[Tennessee River]], the basin includes several states of the [[southeastern United States]]. It is the source of [[drinking water]] for five million people.<ref>{{Cite web|url=https://ohioriverfdn.org/ohio-river/quick-facts/|title=Quick Facts &#124; The Ohio River|access-date=October 23, 2022|archive-date=October 23, 2022|archive-url=https://web.archive.org/web/20221023225820/https://ohioriverfdn.org/ohio-river/quick-facts/|url-status=live}}</ref>

The river became a primary transportation route for pioneers during the westward expansion of the early U.S. The lower Ohio River just below [[Louisville]] was obstructed by rapids known as the [[Falls of the Ohio]] where the elevation falls {{convert|26|ft|m}} in {{convert|2|mi|km}} restricting larger commercial navigation, although in the 18th and early 19th century its three deepest channels could be traversed by a wide variety of craft then in use. In 1830, the [[Louisville and Portland Canal]] (now the [[McAlpine Locks and Dam]]) bypassed the rapids, allowing even larger commercial and modern navigation from the [[Forks of the Ohio]] at Pittsburgh to the [[Port of New Orleans]] at the mouth of the Mississippi on the Gulf of Mexico. Since the "canalization" of the river in 1929, the Ohio has not been a natural free-flowing river; today, it is divided into 21 discrete pools or reservoirs by 20 locks and dams for navigation and power generation.<ref>{{cite web | url=https://www.orsanco.org/river-facts/navigational-dams/ohio-river-navigational-dams/ | title=Ohio River Navigational Dams | access-date=May 10, 2023 | archive-date=May 10, 2023 | archive-url=https://web.archive.org/web/20230510172510/https://www.orsanco.org/river-facts/navigational-dams/ohio-river-navigational-dams/ | url-status=live}}</ref>

The name "Ohio" comes from the [[Seneca language|Seneca]], {{lang|see|Ohi:yo'}}, <small>lit.</small>&nbsp;"Good&nbsp;River".<ref name="Bright" /> In his ''[[Notes on the State of Virginia]]'' published in 1781–82, [[Thomas Jefferson]] stated: "The Ohio is the most beautiful river on earth. Its current gentle, waters clear, and bosom smooth and unbroken by rocks and rapids, a single instance only excepted."<ref>{{cite book |last=Jefferson|first= Thomas|date=1781–1782|title= Notes on the State of Virginia |url=http://etext.virginia.edu/etcbin/toccer-new2?id=JefVirg.sgm&images=images/modeng&data=/texts/english/modeng/parsed&tag=public&part=all |url-status= |location= |publisher= |isbn= |archive-url= https://web.archive.org/web/20130829133128/http://etext.virginia.edu/etcbin/toccer-new2?id=JefVirg.sgm&images=images%2Fmodeng&data=%2Ftexts%2Fenglish%2Fmodeng%2Fparsed&tag=public&part=all |archive-date= August 29, 2013}}. The ''single instance'' refers to the former [[Falls of the Ohio National Wildlife Conservation Area|rapids near Louisville]].</ref>

After the [[French and Indian War]], Britain's [[trans-Appalachia]]n [[Indian Reserve]] was divided by the river into colonial lands to the south and Native American lands to the north. In the late 18th century, the river became the southern boundary of the [[Northwest Territory]]. The river was in the early 19th century considered the western extension of the [[Mason–Dixon line]] that divided [[Pennsylvania]] from [[Maryland]], and thus part of the border between [[Slave states and free states|free]] and [[Slavery in the United States|slave]] territory, and between the [[Northern United States|Northern]] and [[Southern United States]] or [[Upland South]]. Where the river was narrow, it was crossed by thousands of slaves escaping to the North for freedom; many were helped by free blacks and whites of the [[Underground Railroad]] resistance movement.

The Ohio River is a climatic transition area, as its water runs along the periphery of the [[humid continental]] and [[humid subtropical]] climate areas. It is inhabited by fauna and flora of both climates. Today, the Ohio River is [[List of most-polluted rivers|one of the most polluted rivers]] in the United States. During winter, it regularly freezes over in Pittsburgh but rarely farther south towards [[Cincinnati]] and Louisville. Further down the river in places like [[Owensboro]] and [[Paducah]], closer to its confluence with the Mississippi, the Ohio is ice-free year-round.

==Etymology==
The name "Ohio" comes from the [[Seneca language]] (an [[Iroquoian language]]), {{lang|see|Ohi:yo'}} (roughly pronounced oh-hee-yoh, with the vowel in "hee" [[vowel length|held longer]]), a proper name derived from {{lang|see|ohiːyoːh}} ("good&nbsp;river"), therefore literally translating to "Good&nbsp;River".<ref name="Bright">{{cite book |last=Bright |first= William |author-link=William Bright |year=2004 |url = https://books.google.com/books?id=5XfxzCm1qa4C&pg=PA344 |title=Native American Placenames of the United States |publisher=[[University of Oklahoma Press]] |page=344 |isbn=978-0-8061-3598-4 |access-date=April 11, 2011}}</ref><ref>{{cite web |url = http://americanindianstudies.osu.edu/ohio.cfm |title=Native Ohio |access-date=February 25, 2007 |website=American Indian Studies |publisher=[[Ohio State University]] |archive-url = https://web.archive.org/web/20070202230727/http://americanindianstudies.osu.edu/ohio.cfm <!-- Bot retrieved archive --> |archive-date = February 2, 2007 |quote=Ohio comes from the Seneca (Iroquoian) 'ohiiyo' 'good river'}}</ref> "Great river" and "large creek" have also been given as translations.<ref>{{cite web |url=http://www.ohiohistorycentral.org/ohio_quick_facts.php |title=Quick Facts About the State of Ohio |publisher=Ohio History Central |access-date=July 2, 2010 |quote=From Iroquois word meaning 'great river' |archive-date=February 8, 2009 |archive-url=https://web.archive.org/web/20090208222032/http://www.ohiohistorycentral.org/ohio_quick_facts.php |url-status=live}}</ref><ref name="mithun312">{{cite book |first=Marianne |last=Mithun |year=1999 |chapter=Borrowing |chapter-url=https://books.google.com/books?id=ALnf3s2m7PkC&pg=PA311 |pages=311–3 |title=The Languages of Native North America |publisher=Cambridge University Press |location=Cambridge |isbn=978-0-521-29875-9 |quote=Ohio ('large creek') |access-date=September 29, 2018 |archive-date=July 14, 2023 |archive-url=https://web.archive.org/web/20230714233112/https://books.google.com/books?id=ALnf3s2m7PkC&pg=PA311 |url-status=live}}</ref>

[[Native Americans in the United States|Native Americans]], including the [[Lenape]] and [[Iroquois]], considered the Ohio and [[Allegheny River|Allegheny]] rivers as the same, as is suggested by a New York State road sign on [[Interstate 86 (Pennsylvania–New York)|Interstate 86]] that refers to the Allegheny River also as {{lang|see|Ohi:yo'}}.<ref>{{cite book|title=Names on the Land|last=Stewart|first=George R.|publisher=Houghton Mifflin Company|year=1967|isbn=978-0-938530-02-2|location=Boston, Massachusetts|page=8}}<!--|access-date=May 10, 2009--></ref> Similarly, the [[Geographic Names Information System]] lists ''O-hee-yo'' and ''O-hi-o'' as variant names for the Allegheny.<ref>{{cite gnis | id = 1209386 | name = Allegheny River | access-date = May 13, 2010}}</ref>

An earlier [[Miami-Illinois language]] name was also applied to the Ohio River, {{lang|mia|Mosopeleacipi}} ("river of the [[Mosopelea]]" tribe). Shortened in the [[Shawnee language]] to {{lang|sjw|pelewa thiipi}}, {{lang|sjw|spelewathiipi}} or {{lang|sjw|peleewa thiipiiki}}, the name evolved through variant forms such as "Polesipi", "Peleson", "Pele Sipi" and "Pere Sipi", and eventually stabilized to the variant spellings "Pelisipi", "Pelisippi" and "Pellissippi". Originally applied just to the Ohio River, the "Pelisipi" name later was variously applied back and forth between the Ohio River and the [[Clinch River]] in [[Virginia]] and [[Tennessee]].<ref name="pstcc">{{cite web | url = http://www.pstcc.edu/blogs/marketing-comm/?p=6971 | title = The Winding River Home: Pellissippi State researches the meaning of 'Pellissippi' | work = Pellissippi State News | publisher = [[Pellissippi State Community College]] | date = June 7, 2017 | access-date = July 26, 2018 | url-status = live | archive-url = https://web.archive.org/web/20180726041013/http://www.pstcc.edu/blogs/marketing-comm/?p=6971#.W1xpkxlm2M8 | archive-date = July 26, 2018}}</ref><ref>{{Cite web| title = Shawnees Webpage| work = Shawnee's Reservation| access-date = April 26, 2013| year = 1997| url = http://reocities.com/SouthBeach/Cove/8286/speach.html| url-status = dead| archive-url = https://archive.today/20130630052603/http://reocities.com/SouthBeach/Cove/8286/speach.html| archive-date = June 30, 2013}}</ref> In his original draft of the [[Land Ordinance of 1784]], [[Thomas Jefferson]] proposed a new state called "Pelisipia", to the south of the Ohio River, which would have included parts of present-day Eastern [[Kentucky]], Virginia and [[West Virginia]].<ref name="pstcc" />

==History==
===Precolumbian===
[[File:Steamboat "Morning Star", 1858.jpg|thumb|Steamboat ''Morning Star'', a Louisville and Evansville mail packet, in 1858]]
The river had great significance in the history of the [[Native Americans in the United States|Native Americans]], as numerous prehistoric and historic civilizations formed along its valley.<ref>{{cite web |url = https://www.britannica.com/place/Ohio-River |title = Ohio River {{!}} river, United States |website = Encyclopedia Britannica |access-date = February 2, 2019 |archive-date = February 3, 2019 |archive-url = https://web.archive.org/web/20190203032157/https://www.britannica.com/place/Ohio-River |url-status = live}}</ref> For thousands of years, Native Americans used the river as a major transportation and trading route.<ref name="McNeese-2004">{{cite book |last=McNeese |first=Tim |title=The Ohio River |publisher=Chelsea House Publishing|date = 2004|isbn = 9780791077252}}</ref>

In the five centuries before European colonization, the [[Mississippian culture]] built numerous regional [[chiefdom]]s and major [[Earthworks (archaeology)|earthwork mounds]] in the Ohio Valley like the [[Angel Mounds]] near [[Evansville, Indiana]] as well as in the [[Mississippi Valley]] and the Southeast. The historic [[Osage Nation|Osage]], [[Omaha people|Omaha]], [[Ponca]], and [[Kaw (tribe)|Kaw]] peoples lived in the Ohio Valley. Under pressure over the fur trade from the [[Iroquois]] nations to the northeast, they migrated west of the Mississippi River in the 17th century to the territory now defined as [[Missouri]], [[Arkansas]], and [[Oklahoma]].

===European discovery===
Several accounts exist of the discovery and traversal of the Ohio River by Europeans in the latter half of the 17th century: Virginian colonist [[Abraham Wood]]'s trans-Appalachian expeditions between 1654 and 1664;<ref>{{Cite book|url=https://books.google.com/books?id=ngz-jTApvNoC&q=abraham+wood+ohio+river&pg=PA28|title=A History of Appalachia |last=Drake|first=Richard B.|date=August 1, 2003 |publisher=University Press of Kentucky|isbn=978-0-8131-9060-0 |access-date=October 19, 2020 |archive-date= July 14, 2023|archive-url=https://web.archive.org/web/20230714233113/https://books.google.com/books?id=ngz-jTApvNoC&q=abraham+wood+ohio+river&pg=PA28|url-status= live}}</ref> Frenchman [[Robert de La Salle]]'s putative Ohio expedition of 1669;<ref>{{cite web |url=http://www.ohiohistorycentral.org/w/Rene_R._de_La_Salle |title= Rene R. de La Salle |website=Ohio History Central |access-date=April 27, 2019 |archive-date=April 27, 2019 |archive-url=https://web.archive.org/web/20190427204508/http://www.ohiohistorycentral.org/w/Rene_R._de_La_Salle |url-status=live}}</ref> and two expeditions of Virginians sponsored by Colonel Wood: the [[Batts and Fallam expedition]] of 1671,<ref name="ricebrown" /> and the Needham and Arthur expedition of 1673–74.<ref>{{cite web|url=https://www.wvencyclopedia.org/articles/1620 |title=Needham and Arthur Expedition|website=The West Virginia Encyclopedia|access-date=April 27, 2019|archive-date=April 27, 2019|archive-url= https://web.archive.org/web/20190427204510/https://www.wvencyclopedia.org/articles/1620 |url-status=live}}</ref><ref>Who gets credit for discovering the ''Ohio'' River may depend on where one places the headwaters: in colonial times, the Allegheny extended to the mouth of the Kanawha; today, the headwaters of the Ohio are placed at the mouth of the Monongehela.</ref><ref>{{cite web |url=https://digital.library.pitt.edu/islandora/object/pitt:31735057893269/viewer#page/22/mode/2up |title=The Planting of civilization in western Pennsylvania |publisher=University of Pittsburgh Press |year=1967 |website=University of Pittsburgh Press Digital Editions |page=47 |access-date= April 27, 2019 |archive-date=April 27, 2019 |archive-url=https://web.archive.org/web/20190427203801/https://digital.library.pitt.edu/islandora/object/pitt%3A31735057893269/viewer#page/22/mode/2up |url-status=live}}</ref><ref>{{cite book |url=https://books.google.com/books?id=ZlWSdSV2cQQC&pg=PA16 |title=Ohio River |last=McNeese |first=Tim |year=2004 |publisher=Infobase Publishing |isbn=9781438125206 |pages=16 |access-date=April 27, 2019 |archive-date=July 14, 2023 |archive-url=https://web.archive.org/web/20230714233113/https://books.google.com/books?id=ZlWSdSV2cQQC&pg=PA16 |url-status=live}}</ref>

===Exploration and settlement===
===={{anchor|Arnout Viele, 1693}}Arnout Viele (1693)====
In early autumn 1692, loyal English-speaking [[New Amsterdam|Dutchman]] Arnout Viele and a party of eleven companions from [[Esopus, New York|Esopus]]<ref name=Hanna2>{{cite book |last=Hanna |first=Charles Augustus |title=The Wilderness Trail |volume=2 |publisher=G.P. Putnam's Sons |location=New York |date=1911 |url={{google books|1k4zAQAAMAAJ|plainurl=yes}}}}</ref>—Europeans, [[Shawnee]], and a few loyal Delaware guides—were sent by the governor of New York to trade with the Shawnee and bring them into the English sphere of influence.<ref name=buck>{{cite book |last1=Buck |first1=Solon J. |last2=Buck |first2=Elizabeth |title=The Planting of Civilization in Western Pennsylvania |url={{google books|eHz4jgmAhMIC|plainurl=yes|page=47}} |publisher=University of Pittsburgh Press |date=1995 |orig-year=1939 |page=47 |edition=third |isbn=978-0-8229-7405-5}}</ref><ref name=allen>{{cite book |editor-last=Allen |editor-first=John Logan |title=North American Exploration |volume=2: A Continent Defined |publisher=University of Nebraska Press |location=Lincoln, Nebraska |date=1997 |page=311 |url={{google books|8N4ckSmAiL0C|plainurl=yes|page=311}} |isbn=978-0-8032-1023-3}}</ref> Viele understood several Native American languages, which made him valuable as an interpreter. He is credited with being the first European to travel and explore [[western Pennsylvania]] and the upper Ohio Valley. Viele made contact with Native American nations as far west as the [[Wabash River]], in present-day Indiana.<ref name=allen/>

He and his company left [[Albany, New York|Albany]], traveling southbound and crossing portions of present-day New Jersey and eastern Pennsylvania. They apparently followed the [[Susquehanna River#West Branch Susquehanna|west branch of the Susquehanna River]] into the mountains, traversing the [[Tioga River (Chemung River tributary)|Tioga River]] and reaching a tributary of the [[Allegheny River]] before floating down to the Shawnee towns along the Ohio River.<ref name=allen/> Viele and his expedition spent most of 1693 exploring the Ohio River and its tributaries in northern Kentucky with their Shawnee hosts.<ref name=allen/> Gerit Luykasse, two of Viele's Dutch traders, and two Shawnee reappeared in Albany in February 1694 "to fetch powder for Arnout [Viele] and his Company";<ref name=allen/> their party had been gone for fifteen months, but Viele was away for about two years.<ref name=ricebrown>{{cite book |last1=Rice |first1=Otis K. |last2=Brown |first2=Stephen W. |title=West Virginia: A History |publisher=University Press of Kentucky |location=Lexington |edition=Second |date=1993 |orig-year=1985 |url={{google books|zlVw7sa3jocC|plainurl=yes|page=13}} |page=13 |isbn=978-0-8131-3766-7}}</ref> He and his companions returned from the Pennsylvania wilderness in August 1694, accompanied by diplomats from "seven Nations of Indians" who sought trade with the English (or peace with the powerful Iroquois nations of New York and Pennsylvania), and hundreds of Shawnee who intended to relocate in the [[Minisink]] country on the upper [[Delaware River]].<ref name=buck/><ref name=allen/>

===={{anchor|Gaspard-Joseph Chaussegros de Léry, 1729}}Gaspard-Joseph Chaussegros de Léry (1729)====
{{Further|Land surveying in Kentucky}}
In 1729, [[Gaspard-Joseph Chaussegros de Léry (1682–1756)|Gaspard-Joseph Chaussegros de Léry]], a French architect and surveyor whose survey was the first [[Cartography|mapping]] of the Ohio River,<ref name=jillson>{{cite web |last=Jillson |first=Willard Rouse |title=Big Bone Lick: An Outline of Its History, Geology and Paleontology |date=1936 |page=3 |publisher=Standard Printing Company |url=http://bigbonelickkentucky.blogspot.com/2015/01/captain-charles-lemoyne-de-longueil-and.html |access-date=May 7, 2023 |archive-date=July 21, 2015 |archive-url=https://web.archive.org/web/20150721082537/http://bigbonelickkentucky.blogspot.com/2015/01/captain-charles-lemoyne-de-longueil-and.html |url-status=live}}</ref> led an expedition of French troops from Fort Niagara down the [[Allegheny River|Allegheny]] and Ohio Rivers as far as the mouth of the [[Great Miami River]] near Big Bone Lick and possibly the Falls of the Ohio (present-day [[Louisville]]).<ref name=Hanna2/><ref>{{cite web |last=Bogan |first=Dallas |title=Story of the Longhunters in the Beginning |website=History of Campbell County, Tennessee |url=http://www.tngenweb.org/campbell/hist-bogan/Longhunters-beginning.html |access-date=October 27, 2015 |archive-date=November 25, 2015 |archive-url=https://web.archive.org/web/20151125060031/http://www.tngenweb.org/campbell/hist-bogan/Longhunters-beginning.html |url-status=live}}</ref><ref>{{cite book |last=Henderson |first=Archibald |chapter=The Long Hunters in the Twilight Zone |title=The Conquest of the Old Southwest: The Romantic Story of the Early Pioneers |chapter-url={{google books|hUcWAAAAYAAJ|plainurl=yes|page=116}} |date=1920 |location=New York |publisher=The Century Co |page=116}}</ref> Chaussegros de Léry mapped the Great Lakes in 1725, and engineered the Niagara fortifications in 1726.<ref name=osmon>{{cite book |last=Osmon |first=Rick |title=The Graves of the Golden Bear: Ancient Fortresses and Monuments of the Ohio |publisher=Grave Distraction |location=Nashville, Tennessee |date=2011 |url={{google books|E8t8AwAAQBAJ|plainurl=yes|page=31}} |page=31 |isbn=978-0-9829-1286-7}}</ref><ref>{{cite book |editor-last=Rickerson |editor-first=Don |title=The Expedition of Baron de Longueuil |url={{google books|jSUCAQAAQBAJ|plainurl=yes|page=7}} |page=7 |date=2013 |orig-year=1939 |edition=digital |publisher=Pennsylvania Historical Society, Federal Works Agency, Work Projects Administration}}</ref>

{{blockquote|I am indebted for the topographical details of the course of this River to M. de Lery, Engineer, who surveyed it with the compass at the time that he descended it with a detachment of French troops in 1729.|[[Jacques-Nicolas Bellin]]{{sfn|Hanna|1911|page=126}} }}

A map of the Ohio River valley, drawn by Bellin from observations by de Lery, is in [[Pierre François Xavier de Charlevoix]]'s ''History of New France''.<ref name=bellin>{{cite book |title=Remarques sur le Carte de l'Amerique Septentrionale |trans-title=Notes on the Map of North America |language=fr |first=Jacques Nicolas |last=Bellin |pages=120–121 |publisher=Didot |location=Paris, France |url={{google books|gtSsoRHgj3sC|plainurl=yes|page=120}} |date=1755}}</ref><ref>{{cite book |last=Rothert |first=Otto Arthur |title=The Outlaws of Cave-in-Rock: Historical Accounts of the Famous Highwaymen |url={{google books|qbe8qRR4OoEC|plainurl=yes|page=18}} |page=18 |publisher=Southern Illinois University Press |date=1996 |isbn=978-0-8093-2034-9}}</ref> The 1744 Bellin map, "Map of Louisiana" ({{langx|fr|Carte de La Louisiane}}), has an inscription at a point south of the Ohio River and north of the Falls: "Place where one found the ivory of Elephant in 1729" ({{langx|fr|endroit ou on à trouvé des os d'Elephant en 1729}}).<ref>{{cite web |title=A Note on a Mistaken Date for the Discovery of Big Bone Lick |website=Big Bone History |last=Duvall |first=James |url=http://www.oocities.org/bigbonehistory/1729-note.html |access-date=October 27, 2015 |archive-date=January 17, 2016 |archive-url=https://web.archive.org/web/20160117054947/http://www.oocities.org/bigbonehistory/1729-note.html |url-status=live}}</ref><ref>{{cite map |title=Carte de la Louisiane cours du Mississipi (sic) et pais voisins |trans-title=Map of Louisiana through the Mississippi and Neighboring Country |language=fr |publisher=Library of Congress |url=https://www.loc.gov/resource/g3700.ct000661/ |date=1744 |location=Paris, France |access-date=May 7, 2023 |archive-date=May 7, 2023 |archive-url=https://web.archive.org/web/20230507224739/https://www.loc.gov/resource/g3700.ct000661/ |url-status=live }}</ref> De Lery's men found teeth weighing {{convert|10|lb|kg|spell=in}} with a diameter of {{convert|5|to|7|in|mm|spell=in}}, tusks {{convert|11|ft|m}} long and {{convert|6–7|in|mm}} in diameter, and thigh bones {{convert|5|ft|m}} long.<ref>{{cite book |last=O'Malley |first=Mimi |chapter=Discovery of a Mastodon Graveyard |title=It Happened in Kentucky: Remarkable Events that Shaped History |date=2011 |orig-year=2006 |edition=2nd |publisher=Morris Book Publishing |chapter-url={{google books|VQfvTMObViIC|plainurl=yes|page=2}} |page=2 |isbn=978-0-7627-6105-0}}</ref> The bones were collected and shipped to Paris, where they were identified as [[mastodon]] remains; they are on display at the [[National Museum of Natural History, France|French National Natural History Museum]].<ref name=jillson/><ref name=osmon/>

===={{anchor|Charles Le Moyne III, Baron de Longueil, 1739}}Charles III Le Moyne, Baron de Longueil (1739)====
[[Charles III Le Moyne]], second [[Baron de Longueuil]] (later the governor of [[Montreal]] and interim governor of [[New France]]), commanded [[Fort Niagara]] from 1726 to 1733.<ref name=jillson/> He led an expedition of 442 men, including Native Americans, from Montreal to war against the [[Chickasaw]] who occupied territory on the lower part of the Mississippi River in the area claimed as [[La Louisiane]].<ref>{{cite book |last=Banta |first=R.E. |title=The Ohio |publisher=University Press of Kentucky |date=1998 |orig-year=1949 |location=Lexington, Kentucky |url={{google books|YNB9OxE_0v8C|plainurl=yes|page=60}} |page=60 |isbn=978-0-8131-2098-0}}</ref> According to [[Gaston Pierre de Lévis]], Duke de Mirepoix, the expedition used the Ohio River as a corridor to the Mississippi.

{{blockquote|Among the officers who accompanied this party were Major de Lignery; Lieutenants, de Vassan, Aubert de Gaspe, Du Vivier, de Verrier, Le Gardeur de St. Pierre, Chevalier de Villiers, de Portneuf, de Sabrevious; Father Vernet, chaplain; Cadets, [[Daniel-Marie Chabert de Joncaire de Clausonne|Joncaire de Closonne]], Le Gai de Joncaire, Drouet de Richarville the younger, Chaussegros de Lery the younger, de Gannes, Chev. Benoist, de Morville, de Selles, and seventeen others. The rank and file consisted of three sergeants, six corporals, six lance corporals, twenty-four soldiers, forty-five ''[[habitants]]'', one hundred and eighty-six [[Iroquois]] from the Sault, forty-one from the [[Lake of Two Mountains]], thirty-two [[Algonquian peoples|Algonquin]] and [[Nipissing First Nation|Nipissing]], fifty [[Abenaki|Abenaqui]] from St. Francois and Bécancour, Quebec; Father La Bretonnier, Jesuit; Queret, missionary.{{sfn|Hanna|1911|page=239}} }}

One of the first reported eyewitness accounts of [[Shannoah]], a Shawnee town, was by le Moyne III in July 1739. On their journey down the Ohio River toward the Mississippi, they met with local chiefs in a village on the [[Scioto River]].

===={{anchor|John Howard and John Peter Salling, 1742}}John Howard and John Peter Salling (1742)====
John Howard, a pioneer from Virginia, led a party of five—[[John Peter Salling]] (a Pennsylvania German),<ref name=draper>{{cite book |last=Draper |first=Lyman C. |title=Life of Daniel Boone |url={{google books|6npr_LGJH-cC|plainurl=yes|page=47}} |publisher=Stackpole Books |location=Mechanicsburg, Pennsylvania |date=1998 |isbn=978-0-8117-0979-8}}</ref> Josiah Howard (John's son), Charles Sinclair, and John Poteet (Vizt)—from the Virginia mountains to the Mississippi River.<ref>{{cite book |last=Durret |first=Reuben Thomas |title=John Filson, The First Historian of Kentucky |url={{google books|xrYUAAAAYAAJ|plainurl=yes|page=31}} |publisher=John P. Morton & Co |page=31 |date=1884 |location=Louisville, Kentucky}}</ref> The elder Howard had a promised reward of {{convert|10,000|acre|ha}} of land for a successful expedition from the Virginia Royal Governor's Council to reinforce British claims in the west. Howard offered equal shares of the 10,000 acres to the four other members of his expedition. The party of five left John Peter Salling's house in August County on March 16, 1742, and traveled west to [[Cedar Creek (North Fork Shenandoah River tributary)|Cedar Creek]] (near the Natural Bridge), crossing [[Greenbrier River]] and landing at the [[New River (Kanawha River tributary)|New River]]. At New River, the Virginia explorers built a large [[bull boat]] frame and covered it with five buffalo skins. The first Englishmen to explore the region then followed the New River for {{convert|250|mi|km}}, until it became too dangerous to navigate. At a large waterfall, they traveled overland to the [[Coal River (West Virginia)|Coal River]]. Following the [[Kanawha River]], they entered the Ohio River {{convert|444|mi|km}} above the falls. The Virginia pioneers traced the northern boundary of Kentucky for {{convert|500|mi|km|spell=in}}, reaching the [[Mississippi River]] on June 7.<ref name="harrison">{{cite book|last1=Harrison|first1=Lowell H.|url=https://books.google.com/books?id=63GqvIN3l3wC|title=A New History of Kentucky|last2=Klotter|first2=James C.|date=1997|publisher=University Press of Kentucky|location=Lexington|pages=7–8|isbn=9780813120089 |author-link1=Lowell H. Harrison|author-link2=James C. Klotter|access-date=May 30, 2015|archive-date=July 14, 2023|archive-url=https://web.archive.org/web/20230714233118/https://books.google.com/books?id=63GqvIN3l3wC|url-status=live}}</ref><ref name=forbes>{{cite encyclopedia |last=Forbes |first=Harold Malcolm |title=John Peter Salling |encyclopedia=The West Virginia Encyclopedia |edition=online |date=October 29, 2010 |url=http://www.wvencyclopedia.org/articles/167 |publisher=West Virginia Humanities Council |access-date=May 7, 2023 |archive-date=May 28, 2023 |archive-url=https://web.archive.org/web/20230528032520/https://www.wvencyclopedia.org/articles/167 |url-status=live }}</ref><ref>{{cite journal |last=Batman |first=Richard |title=The Odyssey of John Peter Salley |journal=Virginia Cavalcade |date=Summer 1981 |volume=31 |issue=1 |url=https://www.lva.virginia.gov/public/guides/cavalcade/volumes/v31_40/sum81.htm |url-access=subscription |access-date=May 7, 2023 |archive-date=May 7, 2023 |archive-url=https://web.archive.org/web/20230507224205/https://www.lva.virginia.gov/public/guides/cavalcade/volumes/v31_40/sum81.htm |url-status=live}}</ref><ref>{{cite journal |last=Harrison |first=Fairfax |title=The Virginians on the Ohio and the Mississippi in 1742 |journal=Virginia Magazine of History and Biography |date=April 1922 |volume=30 |issue=2 |pages=203–222 |publisher=Virginia Historical Society |jstor=4243878}}</ref><ref name=rice>{{cite book |last=Rice |first=Otis K. |title=Frontier Kentucky |url={{google books|EsoeBgAAQBAJ|plainurl=yes|page=7}} |page=7 |date=1993 |publisher=University Press of Kentucky |location=Lexington |isbn=978-0-8131-1840-6}}</ref> They descended just below the mouth of the [[Arkansas River]], where they were ambushed by a large company of Native Americans, Blacks and Frenchmen on July 2, 1742; one or two of Howard's men were killed.<ref>{{cite book |editor-last=Simon |editor-first=Kevin F. |title=The WPA Guide to Kentucky |url={{google books|e6YfBgAAQBAJ|plainurl=yes|page=36}} |page=36 |date=1996 |orig-year=1939 |edition=reprint |publisher=University Press of Kentucky |location=Lexington |isbn=978-0-8131-5869-3}}</ref> The rest were brought to [[New Orleans]] and imprisoned as spies.<ref name=draper/> After two years in prison, Salling escaped on October 25, 1744, and returned on a southern route to his home in [[Augusta County, Virginia]], in May 1745. John Howard was extradited to France to stand trial. His ship was intercepted by the English and, as a free man, he reported his adventures after landing in London; however, his account has been lost.<ref name=harrison/><ref name=rice/> Salling's detailed account of Virginia's adjacent lands was used in Joshua Fry and Peter Jefferson's 1751 map.<ref name=harrison/><ref name=rice/>

In 1749, the [[Ohio Company]] was established in [[Virginia Colony]] to settle and trade in the Ohio River region. Exploration of the territory and trade with the Indians in the region near the [[Forks of the Ohio|Forks]] brought white colonists from both [[Province of Pennsylvania|Pennsylvania]] and Virginia across the mountains, and both colonies claimed the territory. The movement across the Allegheny Mountains of Anglo-American settlers and the claims of the area near modern-day Pittsburgh led to conflict with the French, who had forts in the [[Ohio Country|Ohio River Valley]]. This conflict was called the [[French and Indian War]], and would merge into the global Anglo-French struggle, the [[Seven Years' War]]. In 1763, following its defeat in the war, France ceded its area east of the Mississippi River to [[Kingdom of Great Britain|Britain]] and its area west of the Mississippi River to [[Spain]] in the [[1763 Treaty of Paris]].

The 1768 [[Treaty of Fort Stanwix]] with several tribes opened Kentucky to colonial settlement and established the Ohio River as a southern boundary for American Indian territory.<ref>{{cite book |last=Taylor |first=Alan |title=The Divided Ground: Indians, Settlers, and the Northern Borderland of the American Revolution |year=2006 |publisher=Alfred A. Knopf |location=New York, NY |isbn=978-0-679-45471-7 |page=[https://archive.org/details/dividedgroundind0000tayl/page/44 44, see map on 39] |url=https://archive.org/details/dividedgroundind0000tayl/page/44 }}</ref> In 1774 the [[Quebec Act]] restored the land east of the Mississippi River and north of the Ohio River to [[Province of Quebec (1763–1791)|Quebec]], in effect making the Ohio the southern boundary of [[Canada]]. This appeased [[French Canadians]] in Quebec but angered the colonists of the [[Thirteen Colonies]]. [[Lord Dunmore's War]] south of the Ohio river also contributed to cession of land north to Quebec to prevent colonial expansion onto Native American territory. During the [[American Revolutionary War|Revolutionary War]]. in 1776 the British military engineer [[John Montrésor]] created a map of the river showing the strategic location of [[Fort Pitt (Pennsylvania)|Fort Pitt]], including specific navigational information about the Ohio River's rapids and tributaries in that area.<ref>{{cite web |last=Montrésor |first=John |url=http://www.wdl.org/en/item/9581/ |year=1776 |title=Map of the Ohio River from Fort Pitt |work=[[World Digital Library]] |location=Pennsylvania |access-date=July 1, 2013 |archive-date=July 15, 2013 |archive-url=https://web.archive.org/web/20130715005545/http://www.wdl.org/en/item/9581/ |url-status=live }}</ref> However, the [[1783 Treaty of Paris]] gave the entire Ohio Valley to the [[United States]], and numerous white settlers entered the region.

[[File:Wheeling Suspension Bridge Lithograph.jpg|thumb|Built between 1847 and 1849, the [[Wheeling Suspension Bridge]] was the first bridge across the river and a crucial part of the National Road.]]
The economic connection of the [[Ohio Country]] to the [[East Coast of the United States|East]] was significantly increased in 1818 when the [[National Road]] being built westward from [[Cumberland, Maryland]], reached [[Wheeling, Virginia]], (now [[West Virginia]]), providing an easier overland connection from the [[Potomac River]] to the Ohio River.<ref name="WDL2">{{cite web |last=Fowler |first=Thaddeus Mortimer |url=http://www.wdl.org/en/item/11374/ |title=Bird's Eye View of Cumberland, Maryland 1906 |website=[[World Digital Library]] |year=1906 |access-date=July 22, 2013 |archive-date=October 3, 2013 |archive-url=https://web.archive.org/web/20131003004014/http://www.wdl.org/en/item/11374/ |url-status=live}}</ref> The [[Wheeling Suspension Bridge]] was built over the river at Wheeling from 1847 to 1849, making the trip west easier. For a brief time, until 1851, it was the world's largest suspension bridge. The bridge survived the [[American Civil War]], after having been improved in 1859. It was renovated again in 1872, and remains in use as the oldest vehicular suspension bridge in the U.S.

[[Louisville]] was founded in 1778 as a military encampment on [[Corn Island (Kentucky)|Corn Island]] (now submerged) by General George Rogers Clark at the only major natural navigational barrier on the river, the [[Falls of the Ohio]]. The Falls were a series of rapids where the river dropped {{convert|26|ft|sp=us}} in a stretch of about {{convert|2|mi|sp=us}}. In this area, the river flowed over hard, fossil-rich beds of [[limestone]]. The outpost was moved that same year to the south shore where [[Fort-on-Shore]] was constructed. It proved insufficient within three years, and the mighty [[Fort Nelson (Kentucky)|Fort Nelson]] was constructed upriver. The town of Louisville was chartered in 1780, in honor of King Louis XVI of France. The first [[Lock (water transport)|locks]] on the river {{ndash}} the [[Louisville and Portland Canal]] {{ndash}} were built between 1825 and 1830 to circumnavigate the falls. Fears that Louisville's transshipment industry would collapse proved ill-founded: but the increasing size of steamships and barges on the river meant that the outdated locks could serve only the smallest vessels until well after the [[American Civil War|Civil War]] when improvements were made. The [[U.S. Army Corps of Engineers]] improvements were expanded again in the 1960s, forming the present-day [[McAlpine Locks and Dam]].

===Nineteenth century===
During the nineteenth century, emigrants from Virginia, North Carolina and Kentucky traveled by the river and settled along its northern bank. Known as [[butternut (people)|butternuts]], they formed the dominant culture in the southern portions of Ohio, Indiana and Illinois with a society that was primarily [[Southern United States|Southern]] in culture. Largely devoted to agricultural pursuits, they shipped much of their produce along the river to ports such as Cincinnati.<ref>Howe, Daniel Walker. ''What Hath God Wrought: The Transformation of America, 1815–1848''. Oxford University Press, 2007. p.136-138</ref>

[[File:Karl Bodmer Travels in America (7).jpg|thumb|left|''Cave-in-rock, view on the Ohio'' (circa 1832, [[Cave-in-Rock State Park|Cave-In-Rock, Illinois]]): aquatint by [[Karl Bodmer]] from the book ''Maximilian, Prince of Wied's Travels in the Interior of North America, during the years 1832–1834'']]
Because the Ohio River flowed westward, it became a convenient means of westward movement by pioneers traveling from western Pennsylvania. After reaching the mouth of the Ohio, settlers would travel north on the Mississippi River to [[St. Louis, Missouri]]. There, some continued on up the [[Missouri River]], some up the Mississippi, and some farther west over land routes. In the early 19th century, [[river pirate]]s such as [[Samuel Mason]], operating out of [[Cave-In-Rock, Illinois]], waylaid travelers on their way down the river. They killed travelers, stealing their goods and scuttling their boats. The folktales about [[Mike Fink]] recall the [[keelboat]]s used for commerce in the early days of American settlement. The Ohio River boatmen inspired performer [[Dan Emmett]], who in 1843 wrote the song "[[The Boatman's Dance]]".

Trading boats and ships traveled south on the Mississippi to [[New Orleans]], and sometimes beyond to the [[Gulf of Mexico]] and other ports in the Americas and Europe. This provided a much-needed export route for goods from the west since the trek east over the [[Appalachian Mountains]] was long and arduous. The need for access to the port of New Orleans by settlers in the Ohio Valley is one of the factors that led to the United States' [[Louisiana Purchase]] in 1803.

===Free states border===
Because the river is the southern border of Ohio, Indiana, and Illinois, it was part of the border between [[free states and slave states]] in the years before the [[American Civil War]]. One antebellum [[Slave trade in the United States|slave trader]] reported that they kept slaves chained two-by-two while navigating the Ohio, only when they reached the Mississippi could the slaves be unchained for a time, because "there was slavery on both sides of the boat."<ref>{{cite book |last=Johnson |first=Walter |title=Soul by Soul: Life Inside the Antebellum Slave Market |publisher=Harvard University Press |year=2009 |isbn=9780674039155 |location=Cambridge |pages=61 |oclc=923120203 |author-link=Walter Johnson (historian)}}</ref> The expression "sold down the river" originated as a lament of Upper South slaves, especially from Kentucky, who were shipped via the Ohio and Mississippi to cotton and sugar plantations in the [[Deep South]]. Changes in crops cultivated in the Upper South resulted in slaves available to be sold to the South, where the expansion of cotton plantations was doing very well. Invention of the [[cotton gin]] made cultivation of short-staple cotton profitable throughout the Black Belt of this region.<ref>{{cite web |url=http://www.ket.org/underground/behind/mendes.htm |work=KET's Underground Railroad: Passage to Freedom, with Kentucky Humanities Association |title=Geography |access-date=December 19, 2018 |archive-url=https://web.archive.org/web/20141020164911/http://www.ket.org/underground/behind/mendes.htm |archive-date=October 20, 2014 |url-status=dead}}</ref><ref>{{cite book |last=Dunaway |first=Wilma A. |chapter=Put in Master's Pocket: Interstate Slave Trading and the Black Appalachian Diaspora |title=Appalachians and Race: The Mountain South from Slavery to Segregation |editor-last=Inscoe |editor-first=John C. |publisher=University Press of Kentucky |year=2000 |pages=5–6 |isbn=978-0813121734 |access-date=December 19, 2018 |quote=Bluegrass dealers made a business of buying up Negroes at auction sales and shipping them down to New Orleans to be sold to owners of cotton and sugar cane plantations... . This practice gave rise to the expression 'sold down the river. |chapter-url=https://docs.google.com/viewer?a=v&pid=sites&srcid=ZGVmYXVsdGRvbWFpbnxkdW5hd2F5d2lsbWF8Z3g6MjgyY2NkZDgxYzJlYWNmMw |chapter-format=DOC |archive-date=May 8, 2021 |archive-url=https://web.archive.org/web/20210508104116/https://docs.google.com/viewer?a=v&pid=sites&srcid=ZGVmYXVsdGRvbWFpbnxkdW5hd2F5d2lsbWF8Z3g6MjgyY2NkZDgxYzJlYWNmMw |url-status=live}}</ref>

Before and during the Civil War, the Ohio River was called the "[[River Jordan]]" by slaves crossing it to escape to freedom in the North via the [[Underground Railroad]].<ref>{{cite web |last=Hudson |first=J. Blaine |title=Crossing the "Dark Line": Fugitive Slaves and the Underground Railroad in Louisville and North Central Kentucky (excerpt) |url=http://www.ket.org/underground/research/crossing.htm |work=KET's Underground Railroad: Passage to Freedom, with Kentucky Humanities Association |access-date=February 25, 2007 |archive-url=https://web.archive.org/web/20130212015127/http://www.ket.org/underground/research/crossing.htm |archive-date=February 12, 2013 |url-status=dead}}</ref> More escaping slaves, estimated in the thousands, made their perilous journey north to freedom across the Ohio River than anywhere else across the north-south frontier. [[Harriet Beecher Stowe]]'s ''[[Uncle Tom's Cabin]]'', the bestselling novel that fueled abolitionist work, was the best known of the anti-slavery novels that portrayed such escapes across the Ohio. The times have been expressed by 20th-century novelists as well, such as the [[Nobel Prize in Literature|Nobel Prize]]-winning [[Toni Morrison]], whose novel ''[[Beloved (novel)|Beloved]]'' was adapted as a film of the same name. She also composed the libretto for the opera ''[[Margaret Garner (opera)|Margaret Garner]]'' (2005), based on the life and trial of an enslaved woman who escaped with her family across the river.

===State border dispute===
The colonial charter for Virginia defined its territory as extending to the north shore of the Ohio, so that the riverbed was "owned" by Virginia. Where the river serves as a boundary between states today, Congress designated the entire river to belong to the states on the east and south, i.e., West Virginia and Kentucky at the time of admission to the Union, that were divided from Virginia. Thus [[Wheeling Island]], the largest inhabited island in the Ohio River, belongs to West Virginia, although it is closer to the Ohio shore than to the West Virginia shore. Kentucky sued the state of Indiana in the early 1980s because of their construction of the never-completed [[Marble Hill Nuclear Power Plant]] in Indiana, which would have discharged its waste water into the river. This would have adversely affected Kentucky's water supplies.

The [[U.S. Supreme Court]] held that Kentucky's jurisdiction (and, implicitly, that of West Virginia) extended only to the low-water mark of 1793 (important because the river has been extensively dammed for navigation so that the present river bank is north of the old low-water mark). Similarly, in the 1990s, Kentucky challenged Illinois's right to collect taxes on [[Harrah's Metropolis|a riverboat casino]] docked in [[Metropolis, Illinois|Metropolis]], citing its own control of the entire river. [[Tropicana Evansville|A private casino riverboat]] that docked in [[Evansville, Indiana]], on the Ohio River opened about the same time. Although such boats cruised on the Ohio River in an oval pattern up and down, the state of Kentucky soon protested. Other states had to limit their cruises to going forward, then reversing and going backward on the Indiana shore only. Both Illinois and Indiana have long since changed their laws to allow riverboat casinos to be permanently docked, with Illinois changing in 1999 and Indiana in 2002.

===Bridge collapse===
[[File:Silver Bridge, 1928.jpg|thumb|right|[[Silver Bridge]] in [[Point Pleasant, West Virginia]], which collapsed into the Ohio River on December 15, 1967, killing 46 people]]
The Silver Bridge at [[Point Pleasant, West Virginia]], collapsed into the river on December 15, 1967. The collapse killed 46 people who had been crossing when the bridge failed. The bridge had been built in 1929, and by 1967 was carrying too heavy a load for its design.<ref>{{cite journal |last=LeRose |first=Chris |date=October 2001 |title=The Collapse of the Silver Bridge |url=http://www.wvculture.org/history/wvhs/wvhs1504.html |journal=West Virginia Historical Society Quarterly |volume=15 |issue=4 |access-date=December 20, 2018 |archive-date=March 6, 2016 |archive-url=https://web.archive.org/web/20160306020500/http://www.wvculture.org/history/wvhs/wvhs1504.html |url-status=live }}</ref> The bridge was rebuilt about one mile downstream and in service as the [[Silver Memorial Bridge]] in 1969.

===Conservation area===
In the early 1980s, the [[Falls of the Ohio National Wildlife Conservation Area]] was established at [[Clarksville, Indiana]].

==Ecology==
{{See also|Water pollution in the United States}}
The Ohio River as a whole is ranked as [[List of most-polluted rivers|the most polluted river in the United States]], based on 2009 and 2010 data. The more industrial and regional West Virginia/Pennsylvania tributary, the [[Monongahela River]], ranked 17th for [[water pollution]], behind 16 other American rivers.<ref>{{cite news |newspaper=[[Pittsburgh Business Times]] |title=Report: Ohio River most polluted in U.S. |access-date=April 24, 2012 |url=http://www.bizjournals.com/pittsburgh/blog/morning-edition/2012/03/report-ohio-river-most-polluted-in-us.html |date=March 23, 2012 |archive-date=April 25, 2012 |archive-url=https://web.archive.org/web/20120425233358/http://www.bizjournals.com/pittsburgh/blog/morning-edition/2012/03/report-ohio-river-most-polluted-in-us.html |url-status=live}}</ref> The Ohio again ranked as the most polluted in 2013, and has been the most polluted river since at least 2001, according to the Ohio River Valley Water Sanitation Commission (ORSANCO). The Commission found that 92% of toxic discharges were [[nitrates]], including farm runoff and waste water from industrial processes such as steel production. The Commission also noted mercury pollution as an ongoing concern, citing a 500% increase in mercury discharges between 2007 and 2013.<ref>{{cite news |last=Bruggers |first=James  |title = Ohio River again tops list for industrial pollution |url = https://www.usatoday.com/story/news/nation/2015/03/14/ohio-river-tops-list-industrial-pollution/24784863/ |newspaper = Louisville Courier Journal |access-date = March 12, 2019 |archive-date = October 23, 2021 |archive-url = https://web.archive.org/web/20211023223447/https://www.usatoday.com/story/news/nation/2015/03/14/ohio-river-tops-list-industrial-pollution/24784863/ |url-status = live}}</ref>

For several decades beginning in the 1950s, the Ohio River was polluted with hundreds of thousands of pounds of [[PFOA]], a fluoride-based chemical used in making [[teflon]], among other things, by the [[DuPont]] chemical company from an outflow pipe at its [[Parkersburg, West Virginia]], facility.<ref name=NYT>{{cite news |last=Rich |first=Nathaniel |title=The Lawyer Who Became DuPont's Worst Nightmare |url=https://www.nytimes.com/2016/01/10/magazine/the-lawyer-who-became-duponts-worst-nightmare.html?_r=0 |newspaper=The New York Times |date=January 6, 2016 |access-date=March 3, 2017 |archive-date=January 9, 2016 |archive-url=https://web.archive.org/web/20160109110502/http://www.nytimes.com/2016/01/10/magazine/the-lawyer-who-became-duponts-worst-nightmare.html?_r=0 |url-status=live}}</ref>

The Ohio was listed among [[America's Most Endangered Rivers]] of 2023 on the heels of contamination from a [[East Palestine, Ohio, train derailment|high-profile train derailment]], and following years as one of the most polluted watersheds in the United States.<ref>{{cite news |last1=Giffin |first1=Connor |title=Ohio River listed as endangered. What that means and what can be done to help. |url=https://www.courier-journal.com/story/news/local/2023/04/20/american-rivers-names-ohio-as-nations-second-most-endangered-river/70127473007/ |access-date=August 8, 2023 |work=The Courier-Journal |date=April 20, 2023 |archive-date=April 26, 2024 |archive-url=https://web.archive.org/web/20240426213017/https://www.courier-journal.com/story/news/local/2023/04/20/american-rivers-names-ohio-as-nations-second-most-endangered-river/70127473007/ |url-status=live }}</ref>

==Economy==
[[File:Barge on Ohio River.jpg|thumb|A barge heads east on the Ohio River in Louisville, Kentucky.]]
The Ohio River is extensively industrialized and populated. Regular barge traffic carries cargoes of oil, [[steel]] and other industrial goods produced in the region. Major cities located along the northern and southern banks of the river include [[Pittsburgh, Pennsylvania]]; [[Louisville, Kentucky]]; [[Evansville, Indiana]]; and [[Cincinnati, Ohio]].<ref name="McNeese-2004" />

==Geography and hydrography==

The combined Allegheny-Ohio river is {{convert|1310|mi}} long and carries the largest volume of water of any tributary of the Mississippi. The Indians and early European explorers and settlers of the region often considered the Allegheny to be part of the Ohio. The [[Point State Park|forks]] (the confluence of the Allegheny and Monongahela rivers at what is now Pittsburgh) were considered a strategic military location by colonial French and British, and later independent American military authorities.

[[File:CairoIL from space annotated.jpg|thumb|left|The [[confluence]] of the [[Mississippi River|Mississippi]] and Ohio rivers is at [[Cairo, Illinois]].]]
The Ohio River is formed by the confluence of the [[Allegheny River|Allegheny]] and [[Monongahela River|Monongahela]] rivers at what is now [[Point State Park]] in [[Pittsburgh]], Pennsylvania. From there, it flows northwest through [[Allegheny County, Pennsylvania|Allegheny]] and [[Beaver County, Pennsylvania|Beaver]] counties, before making an abrupt turn to the south-southwest at the [[West Virginia]]–Ohio–Pennsylvania triple-state line (near [[East Liverpool, Ohio]]; [[Chester, West Virginia]]; and [[Ohioville, Pennsylvania]]). From there, it forms the border between West Virginia and Ohio, upstream of [[Wheeling, West Virginia]].

[[File:Horseshoe bend in Ohio River.jpg|thumb|The Ohio River as seen from [[Fredonia, Indiana]]]]
The river follows a roughly southwest and then west-northwest course until Cincinnati, before bending to a west-southwest course for most of the remainder of its length. The course forms the northern borders of West Virginia and [[Kentucky]]; and the southern borders of [[Ohio]], [[Indiana]] and [[Illinois]], until it joins the [[Mississippi River]] at the city of [[Cairo, Illinois]]. Where the Ohio joins the Mississippi is the lowest elevation in the state of Illinois, at {{convert|315|ft|m}}.

[[File:Floods Recede around the Wabash-Ohio Confluence.jpg|thumb|left|Natural-color satellite image of the Wabash-Ohio confluence]]
The Mississippi River flows to the Gulf of Mexico on the [[Atlantic Ocean]]. Among rivers wholly or mostly in the United States, the Ohio is the second largest by discharge volume and the tenth longest and has the eighth largest drainage basin. It serves to separate the [[Midwestern]] [[Great Lakes]] states from the Upper South states, which were historically [[Border states (American Civil War)|border states]] in the Civil War.

The Ohio River is a left (east) and the largest [[tributary]] by volume of the [[Mississippi River]] in the [[United States]]. At the [[confluence]], the Ohio is considerably bigger than the Mississippi, measured by long-term mean discharge. The Ohio River at Cairo is 281,500&nbsp;cu&nbsp;ft/s (7,960&nbsp;m<sup>3</sup>/s);<ref name=Leeden1990 /> and the Mississippi River at [[Thebes, Illinois]], which is upstream of the confluence, is 208,200&nbsp;cu&nbsp;ft/s (5,897&nbsp;m<sup>3</sup>/s).<ref name=USGS2009>{{cite web |url=http://wdr.water.usgs.gov/wy2009/pdfs/07022000.2009.pdf |title=Water Data Report: 07022000 Mississippi River at Thebes, IL Summary Statistics |publisher=US Geological Survey |access-date=December 19, 2018 |archive-date=November 17, 2017 |archive-url=https://web.archive.org/web/20171117121824/https://wdr.water.usgs.gov/wy2009/pdfs/07022000.2009.pdf |url-status=live }}</ref> The Ohio River flow is greater than that of the Mississippi River, so hydrologically the Ohio River is the main stream of the river system.

===River depth===
[[File:Lawrenceburg-indiana-from-above.jpg|thumb|[[Lawrenceburg, Indiana]], is one of many towns that use the Ohio as a shipping avenue.]]
The Ohio River is a naturally shallow river that was artificially deepened by a series of [[dam]]s. The natural depth of the river varied from about {{convert|3|to|20|ft|m|0}}. The dams raise the water level and have turned the river largely into a series of [[reservoir]]s, eliminating shallow stretches and allowing for commercial navigation. From its origin to Cincinnati, the average depth is approximately {{convert|15|ft|m|0}}. The largest immediate drop in water level is below the McAlpine Locks and Dam at the [[Falls of the Ohio]] at [[Louisville, Kentucky]], where flood stage is reached when the water reaches {{convert|23|ft|m|0}} on the lower gauge. However, the river's deepest point is {{convert|168|ft|m|0}} on the western side of Louisville, Kentucky. From Louisville, the river loses depth very gradually until its confluence with the Mississippi at [[Cairo, Illinois]], where it has an approximate depth of {{convert|19|ft|m|0}}.

Water levels for the Ohio River from Smithland Lock and Dam upstream to Pittsburgh are predicted daily by the [[National Oceanic and Atmospheric Administration]]'s Ohio River Forecast Center.<ref>{{cite web |url=https://www.weather.gov/ohrfc/ |title=Ohio RFC |publisher=US Department of Commerce, NOAA, National Weather Service |access-date=March 10, 2017 |archive-date=March 12, 2017 |archive-url=https://web.archive.org/web/20170312072122/https://www.weather.gov/ohrfc/ |url-status=live}}</ref> The water depth predictions are relative to each local flood plain based upon predicted rainfall in the Ohio River basin in five reports as follows:

* [[Pittsburgh]], Pennsylvania, to [[Hannibal Locks and Dam]], Ohio (including the Allegheny and Monongahela rivers)
* [[Willow Island Locks and Dam]], Ohio, to [[Greenup Lock and Dam]], Kentucky (including the Kanawha River)
* [[Portsmouth, Ohio]], to [[Markland Locks and Dam]], Kentucky
* [[McAlpine Locks and Dam]], Kentucky, to [[Cannelton Locks and Dam]], Indiana
* [[Newburgh Lock and Dam]], Indiana, to [[Golconda, Illinois]]
The water levels for the Ohio River from Smithland Lock and Dam to Cairo, Illinois, are predicted by the [[National Oceanic and Atmospheric Administration]]'s Lower Mississippi River Forecast Center.<ref>{{cite web |url=http://www.weather.gov/lmrfc/ |title=Lower Mississippi RFC |publisher=US Department of Commerce, NOAA, National Weather Service |access-date=March 10, 2017 |archive-date=February 28, 2017 |archive-url=https://web.archive.org/web/20170228181631/http://www.weather.gov/lmrfc/ |url-status=live}}</ref>
* [[Smithland Lock and Dam]], Illinois, to [[Cairo, Illinois]]

{{wide image|PennsylvaniaRailroadBridgePanorama.jpg|5000px|Panorama of the Ohio at its widest point, just west of downtown Louisville, Kentucky|700px|center}}

===List of major tributaries===
The largest tributaries of the Ohio by discharge volume are:
{{Columns-start}}
*Tennessee River {{convert|70575|cuft/s|abbr=on}}
*Cumberland River {{convert|37250|cuft/s|abbr=on}}
*Wabash River {{convert|35350|cuft/s|abbr=on}}
*Allegheny River {{convert|19750|cuft/s|abbr=on}}
*Kanawha River {{convert|15240|cuft/s|abbr=on}}
{{Column}}
*Green River {{convert|14574|cuft/s|abbr=on}}
*Monongahela River {{convert|12650|cuft/s|abbr=on}}
*Kentucky River {{convert|10064|cuft/s|abbr=on}}
*Muskingum River {{convert|8973|cuft/s|abbr=on}}
*Scioto River {{convert|6674|cuft/s|abbr=on}}
{{columns-end}}

By drainage basin area, the largest tributaries are:<ref name="orsanco">{{cite web |title=Tributaries |url=http://www.orsanco.org/river-facts/tributaries/ |website=orsanco.org |access-date=March 13, 2019 |archive-date=March 18, 2019 |archive-url=https://web.archive.org/web/20190318160952/http://www.orsanco.org/river-facts/tributaries/ |url-status=live}}</ref>
{{Columns-start}}
*Tennessee River {{convert|40910|mi2|abbr=on}}
*Wabash River {{convert|33100|mi2|abbr=on}}
*Cumberland River {{convert|17920|mi2|abbr=on}}
*Kanawha River {{convert|12200|mi2|abbr=on}}
*Allegheny River {{convert|11700|mi2|abbr=on}}
{{column}}
*Green River {{convert|9230|mi2|abbr=on}}
*Muskingum River {{convert|8040|mi2|abbr=on}}
*Monongahela River {{convert|7400|mi2|abbr=on}}
*Kentucky River {{convert|6970|mi2|abbr=on}}
*Scioto River {{convert|6510|mi2|abbr=on}}
{{Columns-end}}

The largest tributaries by length are:<ref name="orsanco" />
{{Columns-start}}
*Cumberland River {{convert|693|mi|abbr=on}}
*Tennessee River {{convert|652|mi|abbr=on}}
*Wabash River {{convert|474|mi|abbr=on}}
*Green River {{convert|370|mi|abbr=on}}
*Allegheny River {{convert|325|mi|abbr=on}}
{{column}}
*Licking River {{convert|320|mi|abbr=on}}
*Kentucky River {{convert|255|mi|abbr=on}}
*Scioto River {{convert|237|mi|abbr=on}}
*Great Miami River {{convert|161|mi|abbr=on}}
*Little Kanawha River {{convert|160|mi|abbr=on}}
{{Columns-end}}

Major tributaries, in order from the headwaters, include:<ref name="orsanco" />
{{Columns-start}}
* [[Allegheny River]] – Pittsburgh, Pennsylvania
* [[Monongahela River]] – Pittsburgh
* [[Beaver River (Pennsylvania)|Beaver River]] – [[Rochester, Pennsylvania]]
* [[Little Muskingum River]] – Ohio
* [[Muskingum River]] – Marietta, Ohio
* [[Little Kanawha River]] – [[Parkersburg, West Virginia]]
* [[Hocking River]] – [[Hockingport, Ohio]]
* [[Kanawha River]] – [[Point Pleasant, West Virginia]]
* [[Guyandotte River]] – [[Huntington, West Virginia]]
* [[Big Sandy River (Ohio River)|Big Sandy River]] – Kentucky-West Virginia border
* [[Little Sandy River (Kentucky)|Little Sandy River]] – [[Greenup, Kentucky]]
* [[Little Scioto River (Ohio River)|Little Scioto River]] – [[Sciotoville, Ohio]]
{{column}}
* [[Scioto River]] – [[Portsmouth, Ohio]]
* [[Little Miami River]] – [[Cincinnati, Ohio]]
* [[Licking River (Kentucky)|Licking River]] – [[Newport, Kentucky|Newport]]-[[Covington, Kentucky|Covington]], Kentucky
* [[Great Miami River]] – Ohio-Indiana border
* [[Kentucky River]] – [[Carrollton, Kentucky]]
* [[Salt River (Kentucky)|Salt River]] – [[West Point, Kentucky]]
* [[Green River (Kentucky)|Green River]] – near [[Henderson, Kentucky]]
* [[Wabash River]] – Indiana-Illinois-Kentucky border
* [[Saline River (Illinois)|Saline River]] – Illinois
* [[Cumberland River]] – [[Smithland, Kentucky]]
* [[Tennessee River]] – [[Paducah, Kentucky]]
* [[Cache River (Illinois)|Cache River]] – Illinois
{{Columns-end}}

===Drainage basin===
The Ohio's drainage basin covers {{cvt|203,940|mi2|km2|abbr=on}}, encompassing the easternmost regions of the [[Mississippi Basin]]. The Ohio drains parts of 14 states in four regions.

* Northeast
** [[New York (state)|New York]]: a small area of the southern border along the headwaters of the Allegheny.
** [[Pennsylvania]]: a corridor from the southwestern corner to the north-central border.
* Mid-Atlantic/Upper South
** [[Maryland]]: a small corridor along the [[Youghiogheny River]] on the western border.
** [[West Virginia]]: all but the [[Eastern Panhandle]].
** [[Kentucky]]: all but a small part in the [[Jackson Purchase|extreme west]] drained directly by the Mississippi.
** [[Tennessee]]: all but a small part in the extreme west drained directly by the Mississippi, and a very small area in the southeastern corner which is drained by the [[Conasauga River]].
** [[Virginia]]: most of southwest Virginia.
** [[North Carolina]]: the western quarter.
* Midwest
** [[Ohio]]: 80% (all except a northern strip bordering Lake Erie, and the northwest corner)
** [[Indiana]]: all but the northern area.
** [[Illinois]]: the southeast quarter.
* Deep South
** [[Georgia (U.S. state)|Georgia]]: the far northwest corner.
** [[Alabama]]: the northern portion.
** [[Mississippi]]: the northeast corner.

==Climate transition zone==
The Ohio River is a climatic transition area, as its water runs along the periphery of the [[humid continental]] and [[humid subtropical]] climate areas. It is inhabited by fauna and flora of both climates. In winter, it regularly freezes over at [[Pittsburgh]] but rarely farther south toward [[Cincinnati]] and [[Louisville]]. At [[Paducah, Kentucky]], in the south, at the Ohio's confluence with the Tennessee River, it is ice-free year-round.

In the 21st century, with the 2016 update of climate zones,<ref name="Beck">{{cite journal |last1=Beck |first1=Hylke E. |last2=Zimmermann |first2=Niklaus E. |last3=McVicar |first3=Tim R. |last4=Vergopolan |first4=Noemi |last5=Berg |first5=Alexis|author6-link=Eric Franklin Wood |last6=Wood |first6=Eric F. |title=Present and future Köppen-Geiger climate classification maps at 1-km resolution |journal=Scientific Data |date=October 30, 2018 |volume=5 |article-number=180214 |doi=10.1038/sdata.2018.214 |pmid=30375988 |pmc=6207062 |issn=2052-4463 |bibcode=2018NatSD...580214B}}</ref> the humid subtropical zone has stretched across the river, into the southern portions of [[Ohio#Climate|Ohio]], [[Indiana#Climate|Indiana]], and [[Illinois#Climate|Illinois]].

==Geology==
[[File:Historical Collections of Ohio- An Encyclopedia of the State; History Both General and Local, Geography with Descriptions of Its Counties, Cities and Villages, Its Agricultural, Manufacturing, Mining (14770614544).jpg|thumb|upright=1.5|Glacial Lake Ohio]]

From a geological standpoint, the Ohio River is young. Before the river was created, large parts of [[North America]] were covered by water forming a saltwater lake about 200 miles across and 400 miles in length. The [[bedrock]] of the Ohio Valley was mostly set during this time.<ref name="McNeese-2004" /> The river formed on a piecemeal basis beginning between 2.5 and 3&nbsp;million years ago. By the movement of [[glacier]]s during the earliest [[Laurentide Ice Sheet|ice ages]], the contemporary river [[drainage]]s of the [[Kanawha River|Kanawha]], [[Big Sandy River (Ohio River tributary)|Sandy]], [[Kentucky River|Kentucky]], [[Green River (Kentucky)|Green]], [[Cumberland River|Cumberland]] and [[Tennessee River|Tennessee]] rivers northward created the Ohio system and the course of early [[tributaries]] of the Ohio River, including the [[Monongahela River|Monongahela]] and the [[Allegheny River|Allegheny]] rivers, were set.<ref name="McNeese-2004" /> The [[Teays River]] was the largest of these rivers. The modern Ohio River flows within segments of the ancient Teays. The ancient rivers were rearranged or consumed.

The section of the river that runs southwest from Pittsburgh to [[Cairo, Illinois]], is around tens of thousands of years old.

===Upper Ohio River===
The upper Ohio River formed when one of the glacial lakes overflowed into a south-flowing tributary of the [[Teays River]]. Prior to that event, the north-flowing Steubenville River (no longer in existence) ended between [[New Martinsville]] and [[Paden City, West Virginia]]. The south-flowing Marietta River (no longer in existence) ended between the present-day cities. The overflowing lake carved through the separating hill and connected the rivers. The floodwaters enlarged the small [[Marietta, Ohio|Marietta]] valley to a size more typical of a large river. The new large river subsequently drained glacial lakes and melting glaciers at the end of the ice ages. The valley grew during and following the ice age. Many small rivers were altered or abandoned after the upper Ohio River formed. Valleys of some abandoned rivers can still be seen on satellite and aerial images of the hills of Ohio and West Virginia between Marietta, Ohio, and [[Huntington, West Virginia]].

===Middle Ohio River===
The middle Ohio River formed in a manner similar to that of the upper Ohio River. A north-flowing river was temporarily dammed by natural forces southwest of present-day [[Louisville]], creating a large lake until the dam burst. A new route was carved to the Mississippi. Eventually, the upper and middle sections combined to form what is essentially the modern Ohio River.

==Cities and towns along the river==
Along the banks of the Ohio are some of the largest cities in their respective states:{{NoteTag|Cities and towns of pop. at least 25,000 and among the 10 largest in the state, and whose municipal boundary comes within less than a mile of the river. [[Florence, Kentucky]], a city of 33,500 and that state's eighth-largest, for example, is a near miss because its northernmost boundary only comes within 2.7 miles of the river.}} [[Pittsburgh]], the third-largest city on the river and second-largest in Pennsylvania; [[Cincinnati]], the second-largest city on the river and third-largest in Ohio; [[Louisville]], the largest city on the river and in Kentucky as well; [[Evansville]], the third-largest city in Indiana; [[Owensboro]], the fourth-largest city in Kentucky; and three of the five largest cities in West Virginia—[[Huntington, West Virginia|Huntington]] (second), [[Parkersburg]] (fourth), and [[Wheeling, West Virginia|Wheeling]] (fifth). Only Illinois, among the border states, has no significant cities on the river. There are hundreds of other cities, towns, villages and unincorporated populated places on the river, most of them very small.

Cities along the Ohio are also among the oldest cities in their respective states and among the oldest cities in the United States west of the [[Appalachian Mountains]] (by date of founding): [[Old Shawneetown, Illinois]], 1748; [[Pittsburgh, Pennsylvania]], 1758; [[Wheeling, West Virginia]], 1769; [[Huntington, West Virginia]], 1775; [[Louisville, Kentucky]], 1779; [[Clarksville, Indiana]], 1783; [[Maysville, Kentucky]], 1784; [[Martin's Ferry, Ohio]], 1785; [[Marietta, Ohio]], 1788; [[Cincinnati, Ohio]], 1788; [[Manchester, Ohio]], 1790; [[Beaver, Pennsylvania]], 1792; and [[Golconda, Illinois]], 1798.

Other cities of interest include [[Cairo, Illinois]], at the confluence of the Ohio with the Mississippi River and the southernmost and westernmost city on the river; and [[Beaver, Pennsylvania]], the site of colonial [[Fort McIntosh (Pennsylvania)|Fort McIntosh]] and the northernmost city on the river. It is 548 miles as the crow flies between Cairo and Pittsburgh, but 981 miles by water. Direct water travel over the length of the river is obstructed by the Falls of the Ohio just below Louisville, Kentucky. The [[Ohio River Scenic Byway]] follows the Ohio River through Illinois, Indiana and Ohio ending at [[Steubenville, Ohio]], on the river.

Before there were cities, there were colonial forts. These forts played a dominant role in the [[French and Indian War]], [[Northwest Indian War]] and pioneering settlement of [[Ohio Country]]. Many cities got their start at or adjacent to the forts. Most were abandoned by 1800. Forts along the Ohio river include [[Fort Pitt (Pennsylvania)]], [[Fort McIntosh (Pennsylvania)]], [[Fort Randolph (West Virginia)]], [[Fort Henry (West Virginia)]], [[Fort Harmar]] (Ohio), [[Fort Washington (Ohio)]], and [[Fort-on-Shore]] and [[Fort Nelson (Kentucky)]]. Short-lived, special-purpose forts included [[Fort Steuben]] (Ohio), [[Fort Finney (Indiana)|Fort Finney]] (Indiana), [[Fort Finney (Ohio)|Fort Finney]] (Ohio) and [[Fort Gower]] (Ohio). There was also the [[Newport Barracks]] (Kentucky) in the 19th century.

==Recreation==
{{Expand section|date=August 2024}}
Annual events taking place on or over the river include [[Thunder Over Louisville]], the [[Madison Regatta]], and the [[Great Steamboat Race]].

Multiple [[List of West Virginia State Fishing Records|West Virginia stage record fish]] were caught along the Ohio River.<ref>{{Cite web|title=West Virginia Fishing Records|url=https://wvdnr.gov/fishing/state-records/|access-date=August 25, 2024|publisher=[[West Virginia DNR]]|archive-date=August 24, 2024|archive-url=https://web.archive.org/web/20240824034410/https://wvdnr.gov/fishing/state-records/|url-status=live}}</ref><ref>{{Cite web |title=West Virginia Fishing Records |url=https://www.landbigfish.com/staterecords/records.cfm?state=Westvirginia |access-date=August 25, 2024 |website=Land Big Fish |archive-date=August 26, 2024 |archive-url=https://web.archive.org/web/20240826035808/https://www.landbigfish.com/staterecords/records.cfm?state=Westvirginia |url-status=live }}</ref><ref>{{Cite web |last=Kirk |first=Sam |date=January 10, 2024 |title=West Virginia DNR creates 5 new state fishing record categories |url=https://www.wvnstv.com/outdoors-wildlife/west-virginia-dnr-creates-5-new-state-fishing-record-categories/?nxsparam=1 |access-date=August 25, 2024 |website=[[WBOY]] |archive-date=August 26, 2024 |archive-url=https://web.archive.org/web/20240826035807/https://www.wvnstv.com/outdoors-wildlife/west-virginia-dnr-creates-5-new-state-fishing-record-categories/?nxsparam=1 |url-status=live }}</ref>

==Gallery==
<gallery mode="packed" heights="140">
File:Allegheny Monongahela Ohio.jpg|The [[Allegheny River]], left, and [[Monongahela River]] join to form the Ohio River at [[Pittsburgh]], Pennsylvania, the largest metropolitan area on the river.
File:Cincinnati Ohio.jpg|[[Cincinnati]], Ohio, skyline showing the [[John A. Roebling Suspension Bridge]] to Covington, Kentucky
File:Louisville Skyline 2021 (3).jpg|[[Louisville, Kentucky]]. The deepest point of the Ohio River is a scour hole just below Cannelton locks and dam (river mile 720.7).
File:Donna York.jpg|A barge hauls [[coal]] in the [[Louisville and Portland Canal]], the only artificial portion of the Ohio River.
File:Ohioriver bridge8475.JPG|[[Carl Perkins Bridge]] in [[Portsmouth, Ohio]], with Ohio River and [[Scioto River]] tributary on right
File:Geography of Ohio - DPLA - aaba7b3295ff6973b6fd1e23e33cde14 (page 133) (cropped2).jpg|The Ohio River seen at [[Sciotoville, Ohio|Sciotoville]], from the "Geography of Ohio," 1923
</gallery>

== See also ==
{{div col}}

'''Lists of dams and bridges'''
* [[List of crossings of the Ohio River]]
* [[List of locks and dams of the Ohio River]]

'''Lists of rivers'''
* [[List of variant names of the Ohio River]]
* [[List of longest rivers of the United States (by main stem)]]
* [[List of most-polluted rivers]]
* [[List of rivers of Illinois]]
* [[List of rivers of Indiana]]
* [[List of rivers of Kentucky]]
* [[List of rivers of Ohio]]
* [[List of rivers of Pennsylvania]]
* [[List of rivers of West Virginia]]

'''Ohio Valley, etc.'''
* [[Appalachia]]
* [[Appalachian Ohio]]
* [[Ohio and Erie Canal]]
* [[Ohio River flood of 1937]]
* [[Watersheds of Illinois]]
* [[Ohio River Valley AVA]]
* [[Ohio Valley in Kentucky]]
* [[Ohio River Trail]]
* [[Ohio River Water Trail]]
* [[Falls of the Ohio National Wildlife Conservation Area]]
{{div col end}}

== Notes ==
{{NoteFoot}}

== References ==
{{Reflist}}

== Further reading ==
* {{cite journal |first = J. P. |last = Dunn |date=December 1912 |title = Names of the Ohio River |journal=The Indiana Quarterly Magazine of History |volume=8 |issue=4 |pages=166–70 |jstor = 27785389}}
* {{cite book |last=Hay |first=Jerry M. |year=2010 |title = Ohio River Guidebook |isbn = 978-1605852171 |publisher=Indiana Waterways |edition= 1st |url = https://books.google.com/books?id=-CWFN4uL8L8C}}

==External links==
{{Commons category|Ohio River}}
* [https://waterdata.usgs.gov/pa/nwis/current?type=flow U.S. Geological Survey: PA stream gauging stations]
* [https://www.weather.gov/ohrfc/ NWS Ohio River Forecast Center], which issues official river forecasts for the Ohio River and its tributaries from Smithland Lock and Dam upstream
* [https://www.weather.gov/lmrfc/ Lower Mississippi River Forecast Center], which issues official river forecasts for the Ohio River and its tributaries downstream of Smithland Lock and Dam
* {{Wikisource-inline|list=
** {{Cite EB1911|wstitle=Ohio River|volume=20|short=x|noicon=x}}
** {{Cite AmCyc|wstitle=Ohio River|short=x|noicon=x}}
** {{Cite NIE|wstitle=Ohio River|short=x|noicon=x}}
** {{Cite NSRW|wstitle=Ohio (river)|display=Ohio, a river of the United States|short=x|noicon=x}}
** {{Cite Collier's|wstitle=Ohio (river)|display=Ohio, a river of the United States|short=x|noicon=x}}
}}

{{Clear}}
{{United States topics}}
{{Authority control}}

[[Category:Ohio River| ]]
[[Category:Tributaries of the Mississippi River]]
[[Category:Rivers of Illinois]]
[[Category:Rivers of Indiana]]
[[Category:Rivers of Kentucky]]
[[Category:Rivers of Ohio]]
[[Category:Rivers of Pennsylvania]]
[[Category:Rivers of West Virginia]]
[[Category:Appalachian Ohio]]
[[Category:Borders of Illinois]]
[[Category:Borders of Kentucky]]
[[Category:Borders of Indiana]]
[[Category:Borders of Ohio]]
[[Category:Borders of West Virginia]]
[[Category:Mississippi River watershed]]
[[Category:West Virginia placenames of Native American origin]]
[[Category:Kentucky placenames of Native American origin]]