View source for Lake Ontario

{{short description|Easternmost of Great Lakes in U.S. and Canada}}
{{Redirect-distinguish|Ontario Lake|Ontario Lacus}}
{{Use mdy dates|date=October 2019}}
{{Infobox body of water
 | name                 = Lake Ontario
| native_name       =
 | image                = ISS-36 Lake Ontario (horizontal).jpg
 | caption              = Lake Ontario seen from the [[International Space Station]] on August 24, 2013. The cloudy yellowish substance is [[algal bloom]].  
 | image_bathymetry     = Lake Ontario bathymetry map.png
 | caption_bathymetry   = Lake Ontario [[Bathymetry|bathymetric]] map.<ref name="GLBathOnt" /><ref name="GLBathEr" /><ref name="GLOBE" /> The deepest point is marked with "×".<ref name="NOAA_GLERL" />
 | location             = North America
 | group                = [[Great Lakes]]
 | pushpin_map          = Ontario
 | coords               = {{coord|43.7|N|77.9|W|type:waterbody_scale:3000000|display=inline,title}}
 | lake_type            = [[Glacial lake|Glacial]]
 | etymology            = ''Ontarí:io'', a Huron ([[Wyandot language|Wyandot]]) word meaning "great lake"
 | inflow               = [[Niagara River]]
 | outflow              = [[St. Lawrence River]]
 | catchment            = {{convert|24720|sqmi|km2|abbr=on}}<ref name="EPAphysical"/>
 | basin_countries      = Canada and United States
 | length               = {{convert|193|mi|km|abbr=on}}<ref name=EPA/>
 | width                = {{convert|53|mi|km|abbr=on}}<ref name=EPA/>
 | area                 = {{convert|7323|sqmi|km2|abbr=on}}<ref name="EPAphysical"/>
 | depth                = {{convert|283|ft|m|abbr=on}}<ref name=EPA/>{{sfn|Wright|2006|p=64}}
 | max-depth            = {{convert|802|ft|m|abbr=on}}<ref name=EPA/>{{sfn|Wright|2006|p=64}}
 | volume               = {{convert|391.4|cumi|km3|abbr=on}}<ref name=EPA/>
 | residence_time       = 6 years
| shore = {{convert|634|mi|km|abbr=on}} plus {{convert|78|mi|km|abbr=on}} for islands<ref>[https://www.michigan.gov/deq/0,4561,7-135-3313_3677-15959--,00.html Shorelines of the Great Lakes] {{webarchive|url=https://web.archive.org/web/20150405211915/https://www.michigan.gov/deq/0%2C4561%2C7-135-3313_3677-15959--%2C00.html |date=April 5, 2015 }}</ref>
 | elevation            = {{convert|243|ft|m|abbr=on}}<ref name=EPA/>
 | islands              = 
 | islands_category     = Islands in the Great Lakes
 | cities               = [[Toronto]], [[Ontario]]<br> [[Mississauga]], [[Ontario]]<br>[[Hamilton, Ontario]]<br> [[Rochester, New York]]
 | reference            ={{sfn|Wright|2006|p=64}}
}}
'''Lake Ontario''' ({{langx|fr|'''Lac Ontario'''<!--From https://www12.statcan.gc.ca/census-recensement/2011/geo/map-carte/pdf/2011-12572-35-10.pdf-->}}) is one of the five [[Great Lakes]] of North America. It is bounded on the north, west, and southwest by the Canadian province of [[Ontario]], and on the south and east by the U.S. state of [[New York (state)|New York]]. The [[Canada–United States border]] spans the centre of the lake. On the Canadian side, the major cities are [[Kingston, Ontario|Kingston]], [[Mississauga]], [[Toronto]], [[Hamilton, Ontario|Hamilton]], and [[St. Catharines]]. On the American side, the major cities are [[Rochester, New York|Rochester]] and [[Watertown, New York|Watertown]].

The last in the Great Lakes chain, Lake Ontario serves as the outlet to the Atlantic Ocean via the [[Saint Lawrence River]], comprising the western end of the [[Saint Lawrence Seaway]]. Its primary inlet is the [[Niagara River]] from [[Lake Erie]]. The [[Long Sault Dam|Long Sault control dam]], primarily along with the [[Moses-Saunders Power Dam]] regulates the water level of the lake.<ref>{{cite news |last=Armstrong |first=Leslie |title=Great Lakes Water Levels Rebound Thanks to Prolonged Winter |newspaper=Toronto Star |date=August 14, 2014}}</ref>

The name ''Ontarí'io'' is most often translated from [[Wyandot language|Huron]] as "beautiful lake",<ref name=":0">{{Cite journal |last=Barbeau |first=Marius |date=1961 |title=Legend and History in the Oldest Geographical Names of the St. Lawrence |journal=Inland Seas |volume=17 |issue=2 |pages=112}}</ref><ref>{{Cite book |last=O’Callaghan |first=E.B. |title=Documents Relative to the Colonial History of the State of New-York, vol. IX |publisher=Weed, Parsons and Company |year=1855 |location=Albany, NY |pages=16, 76}}</ref> but other translations exist.<ref>{{Cite journal |last=Wallis |first=Richard P. |date=1958 |title=Names on the Lakes |journal=Inland Seas |volume=14 |issue=1 |pages=16}}</ref>

==Geography==
[[File:Lake Ontario Watershed.png|thumb|Lake Ontario's [[drainage basin]]]]

Lake Ontario is the easternmost of the Great Lakes and the smallest in surface area ({{convert|7,340|mi2|km2|abbr=on|disp=comma}}),<ref name="EPAphysical">{{cite web|url=http://www.epa.gov/glnpo/physfacts.html |title=Great Lakes: Basic Information: Physical Facts |access-date=November 12, 2011 |date=May 25, 2011 |publisher=U.S. Government |url-status=dead |archive-url=https://web.archive.org/web/20120529233616/http://www.epa.gov/glnpo/physfacts.html |archive-date=May 29, 2012 }}</ref> although it exceeds [[Lake Erie]] in volume ({{convert|393|mi3|km3|abbr=on|disp=comma}} to {{convert|116|cumi|km3|abbr=on}}). It is the 13th-largest lake in the world. When its islands are included, the lake's shoreline is {{convert|712|mi|km}} long. As the last lake in the Great Lakes' hydrologic chain, Lake Ontario has the lowest mean surface elevation of the lakes at {{convert|243|ft|m}}<ref name=EPA/> above sea level; {{convert|326|ft|m}} lower than its neighbor upstream. Its maximum length is {{convert|193|smi|km nmi|lk=on|abbr=off}}, and its maximum width is {{convert|53|smi|km nmi}}.<ref name=EPA>{{cite web |url=http://www.epa.gov/glnpo/atlas/gl-fact1.html |title=Great Lakes Atlas: Factsheet #1 |access-date=November 12, 2011 |date=April 11, 2011 |publisher=United States Environmental Protection Agency |url-status=dead |archive-url=https://web.archive.org/web/20111106201816/http://www.epa.gov/glnpo/atlas/gl-fact1.html |archive-date=November 6, 2011  }}</ref> The lake's average depth is 47 [[fathom]]s 1 foot (283&nbsp;ft; 86 m), with a maximum depth of 133 fathoms 4 feet (802&nbsp;ft; 244 m) in the [[Rochester Basin]].<ref name=EPA/>{{sfn|Wright|2006|p=64}} The lake's primary source is the Niagara River, draining Lake Erie, with the Saint Lawrence River serving as the outlet. The [[drainage basin]] covers 24,720&nbsp;square&nbsp;miles (64,030&nbsp;km<sup>2</sup>).<ref name="EPAphysical"/><ref>[http://www.fllowpa.org/statebasin.pdf A Report on Water Resources and Local Watershed Management Programs] {{webarchive|url=https://web.archive.org/web/20110726055920/http://www.fllowpa.org/statebasin.pdf |date=July 26, 2011 }}. The State of the New York Lake Ontario Basin (2000)</ref> As with all the Great Lakes, water levels change both within the year (owing to seasonal changes in water input) and among years (owing to longer-term trends in precipitation). These water level fluctuations are an integral part of [[Lake ecosystem|lake ecology]] and produce and maintain extensive wetlands.<ref>Wilcox, D.A, Thompson, T.A., Booth, R.K., and Nicholas, J.R.. 2007. Lake-level variability and water availability in the Great Lakes. U.S. Geological Survey Circular 1311, 25 p.</ref><ref>Keddy, P.A. 2010. Wetland Ecology: Principles and Conservation (2nd edition). Cambridge University Press, Cambridge, UK. Chapter 2.</ref> The lake also has an important freshwater fishery, although it has been negatively affected by factors including [[overfishing]], water pollution and [[Invasive species in the United States|invasive species]].<ref name="Christie, W. J. 1974">Christie, W. J. (1974). Changes in the fish species composition of the Great Lakes. Journal of the Fisheries Research Board of Canada, 31, 827–54.</ref>

[[Baymouth bar]]s built by prevailing winds and currents have created a significant number of [[lagoon]]s and sheltered harbors, mostly near (but not limited to) [[Prince Edward County, Ontario]], and the easternmost shores. Perhaps the best-known example is [[Toronto Harbour|Toronto Bay]], chosen as the site of the [[Upper Canada]] capital for its strategic harbor. Other prominent examples include [[Hamilton Harbour]], [[Irondequoit Bay]], [[Presqu'ile Provincial Park|Presqu'ile Bay]], and [[Sodus Bay]]. The bars themselves are the sites of long beaches, such as [[Sandbanks Provincial Park]] and [[Sandy Island Beach State Park]]. These sand bars are often associated with large [[wetland]]s, which support large numbers of plant and animal species, as well as providing important rest areas for migratory birds.<ref>Maynard, L., and Wilcox, D.A., 1997, Coastal wetlands of the Great Lakes—State of the Lakes Ecosystem Conference 1996 background paper: Environment Canada and U.S. Environmental Protection Agency, EPA 905–R–97–015b, 99 p.</ref><ref>Keddy, P.A. 2010. Wetland Ecology: Principles and Conservation (2nd edition). Cambridge University Press, Cambridge, UK.497 p.</ref> Presqu'ile, on the north shore of Lake Ontario, is particularly significant in this regard. One unique feature of the lake is the Z-shaped [[Bay of Quinte]] which separates Prince Edward County from the Ontario mainland, save for a {{convert|2|mi|km|adj=on}} isthmus near Trenton; this feature also supports many wetlands and aquatic plants, as well as associated fisheries.

Major rivers draining into Lake Ontario include the [[Niagara River]], [[Don River (Toronto)|Don River]], [[Humber River (Ontario)|Humber River]], [[Rouge River (Ontario)|Rouge River]], [[Trent River (Ontario)|Trent River]], [[Cataraqui River]], [[Genesee River]], [[Oswego River (New York)|Oswego River]], [[Black River (New York)|Black River]], [[Little Salmon River (Lake Ontario)|Little Salmon River]], [[Credit River]], [[Ganaraska River]] and the [[Salmon River (New York)|Salmon River]].

The [[Welland Canal]] also drains into the lake.

==Geology==
The lake basin was carved out of soft, weak [[Silurian]]-age rocks by the [[Wisconsin glaciation|Wisconsin]] ice sheet during the [[Last Glacial Period|last ice age]]. The action of the ice occurred along the pre-glacial [[Ontarian River]] valley which had approximately the same orientation as today's basin. [[Till|Material]] that was pushed southward by the ice sheet left landforms such as [[drumlin]]s, [[kame]]s, and [[moraine]]s, both on the modern land surface and the lake bottom,<ref>[http://www.geology.utoronto.ca/Members/eyles/eyles_bib/RefWorks-507 Origin of drumlins on the floor of Lake Ontario and in upper New York State; Quaternary geology; bridging the gap between East and West — Department of Geology, University of Toronto] {{webarchive|url=https://web.archive.org/web/20110706233403/http://www.geology.utoronto.ca/Members/eyles/eyles_bib/RefWorks-507 |date=July 6, 2011 }}. Geology.utoronto.ca (November 17, 2011). Retrieved on November 29, 2011.</ref> reorganizing the region's entire drainage system. As the ice sheet retreated toward the north, it still dammed the St. Lawrence Valley outlet, so the lake surface was at a higher level. This stage is known as [[Glacial Lake Iroquois|Lake Iroquois]]. During that time the lake drained through present-day [[Syracuse, New York]], into the [[Mohawk River]], thence to the [[Hudson River]] and the Atlantic. The shoreline created during this stage can be easily recognized by the (now dry) beaches and wave-cut hills {{convert|10|to|25|mi|km}} from the present shoreline.

When the ice finally receded from the St. Lawrence valley, the outlet was below [[sea level]], and for a short time, the lake became a [[Inland sea (geology)|bay]] of the Atlantic Ocean, in association with the [[Champlain Sea]]. Gradually the land [[Post-glacial rebound|rebounded]] from the release of the weight of about {{convert|6,500|ft|m}} of ice that had been stacked on it. It is still rebounding about {{convert|12|in|cm}} per century in the St. Lawrence area. Since the ice receded from the area last, the most rapid rebound still occurs there. This means the lake bed is gradually tilting southward, inundating the south shore and [[Ria|turning river valleys into bays]]. Both north and south shores experience shoreline erosion, but the tilting amplifies this effect on the south shore, causing loss to property owners.
[[File:Great Lakes Lake Ontario.png|thumb|Map of [[Great Lakes]] (Lake Ontario in darker blue)]]

==Climate==
[[File:2Lake Ontario.JPG|thumb|[[Hamilton Harbour]] frozen over. Ice sheets can form along the shoreline of Lake Ontario during the winter.]]
The lake has a natural [[seiche]] rhythm of eleven minutes. The seiche effect normally is only about {{convert|3/4|in|cm}} but can be greatly amplified by earth movement, winds, and atmospheric pressure changes. Because of its great depth, the lake as a whole does not completely freeze in winter, but an ice sheet covering between 10% and 90% of the lake area typically develops, depending on the severity of the winter. Ice sheets typically form along the shoreline and in slack water bays, where the lake is not as deep. During the winters of 1877 and 1878, the ice sheet coverage was up to 95–100% of the lake. [[Engagements on Lake Ontario#Operations in 1812|During the War of 1812]], the ice cover was stable enough the American naval commander stationed at Sackets Harbor feared a British attack from Kingston, over the ice. The lake has completely frozen over on five recorded occasions: in 1830,<ref>''Kingston Chronicle,'' January 30, 1830, 2, col. 6 ("For several years past we have not been visited with so much snow as has fallen here within the last fortnight. The storm of Wednesday and yesterday could only be equalled by such visitations as are familiar to our Lower Canada friends. The thermometer has ranged from 10° below, to 20° above 0, for the last ten days. The Lake is firmly frozen, and a cheap and safe style of travelling has revived the intercourse with our brethren of the ''independent'' portion of the world"); ''[[The Republican Compiler]]'' [newspaper], February 23, 1830, p. 2, col. 5 ("At Kingston, Upper Canada, the quantity of snow which had fallen had not been equaled for several years.—The Lake (Ontario) was frozen, and crossing had become general"); Perry, Kenneth A, ''The Fitch Gazetteer: An Annotated Index to the Manuscript History of Washington County, New York,'' 4 vols. (Bowie, Md.: Heritage Books, 1999), 4:565 ("Kingston, Upper Canada, [experiencing] the deepset {{sic}} snow in several yrs., & Lake Ontario frozen over"); ''Kingston Chronicle'' [newspaper], January 9, 1830, 2, col. 1 ("the Bay was frozen across this morning"); ''see also Vermont Chronicle'', (Bellows Falls, Vt.) Friday, February 19, 1830, p. 31, col D, quoting the ''Quebec Gazette'': "The Lake (Ontario) was frozen, and crossing had become general."</ref> 1874, 1893, 1912, and 1934.{{sfn|May|2008}}

When the cold winds of winter pass over the warmer water of the lake, they pick up moisture and drop it as [[lake-effect snow]]. Since the prevailing winter winds are from the northwest, the southern and southeastern shoreline of the lake is referred to as the [[snowbelt]]. In some winters, the area between Oswego and [[Pulaski, New York|Pulaski]] may receive twenty or more feet (600&nbsp;cm) of snowfall. Also impacted by lake-effect snow is the [[Tug Hill|Tug Hill Plateau]], an area of elevated land about {{convert|20|mi|km}} east of Lake Ontario. The "Hill", as it is often referred to, typically receives more snow than any other region in the [[eastern United States]]. As a result, Tug Hill is a popular location for winter enthusiasts, such as snow-mobilers and cross-country skiers. Lake-effect snow often extends inland as far as [[Syracuse, New York|Syracuse]], with that city often recording the most winter snowfall accumulation of any large city in the United States. Other cities in the world receive more snow annually, such as [[Quebec City]], which averages {{convert|135|in|cm}}, and [[Sapporo]], Japan, which receives {{convert|250|in|cm}} each year and is often regarded as the snowiest city in the world.

Foggy conditions (particularly in fall) can be created by thermal contrasts and can be an impediment for recreational boaters. Lake breezes in spring tend to slow fruit bloom until the frost danger is past, and in the autumn delay the onset of fall frost, particularly on the south shore. Cool onshore winds also slow the early bloom of plants and flowers until later in the spring season, protecting them from possible frost damage. Such [[microclimate|microclimatic]] effects have enabled tender fruit production in a continental climate, with the southwest shore supporting a major fruit-growing area. [[Apple]]s, [[cherry|cherries]], [[pear]]s, [[plum]]s, and [[peach]]es are grown in many commercial orchards around Rochester. Between [[Stoney Creek, Ontario|Stoney Creek]] and [[Niagara-on-the-Lake]] on the [[Niagara Peninsula]] is a major fruit-growing and wine-making area. The [[Niagara Escarpment AVA|wine-growing region]] extends over the international border into [[Niagara County, New York|Niagara]] and [[Orleans County, New York|Orleans]] counties in New York. Apple varieties that tolerate a more extreme climate are grown on the lake's north shore, around [[Cobourg]].

==Ecology==
[[File:USGS image cropped.jpg|thumb|Profile of coastal wetlands for Lake Ontario]]
The Great Lakes watershed is a region of high biodiversity, and Lake Ontario is important for its diversity of birds, fish, reptiles, amphibians, and plants. Many of these special species are associated with shorelines, particularly sand dunes, lagoons, and wetlands. The importance of wetlands to the lake has been appreciated, and many of the larger wetlands have protected status. These wetlands are changing, partly because the natural water level fluctuations have been reduced. Many wetland plants are dependent upon low water levels to reproduce.<ref>Keddy, P.A. 2010. Wetland Ecology: Principles and Conservation (2nd edition). Cambridge University Press, Cambridge, UK. 497 p. Chapters 1 and 2.</ref> When water levels are stabilized, the area and diversity of the marsh is reduced. This is particularly true of meadow marsh (also known as [[wet meadow]] wetlands); for example, in Eel Bay near Alexandria Bay, regulation of lake levels has resulted in large losses of wet meadow.<ref>Wilcox, D.A, Thompson, T.A., Booth, R.K., and Nicholas, J.R. 2007. Lake-level variability and water availability in the Great Lakes. U.S. Geological Survey Circular 1311.Box 4</ref> Often this is accompanied by the invasion of [[Typha|cattails]], which displace many of the native plant species and reduce plant diversity. [[Eutrophication]] may accelerate this process by providing nitrogen and phosphorus for the more rapid growth of competitively dominant plants.<ref>Keddy, P.A. 2010. Wetland Ecology: Principles and Conservation (2nd edition). Cambridge University Press, Cambridge, UK. 497 p.</ref> Similar effects are occurring on the north shore, in wetlands such as Presqu'ile, which have interdunal wetlands called [[Salt pannes and pools|pannes]], with high plant diversity and many unusual plant species.<ref>Moore, D. R. J. and Keddy, P. A. (1989). The relationship between species richness and standing crop in wetlands: the importance of scale. Vegetation, 79, 99–106.</ref>
[[File:Lake Ontario food web.pdf|thumb|Lake Ontario's food web]]
Most of the forests around the lake are [[temperate deciduous forest|deciduous forests]] dominated by trees including maple, oak, beech, ash and basswood. These are classified as part of the [[Mixedwood Plains Ecozone (Canada)|Mixedwood Plains Ecozone]] by Environment Canada, or as the [[Eastern Great Lakes and Hudson Lowlands (ecoregion)|Eastern Great Lakes and Hudson Lowlands]] by the [[United States Environmental Protection Agency]], or as the Great Lakes Ecoregion by The Nature Conservancy.<ref>{{cite web |url=http://science.natureconservancy.ca/initiatives/blueprints/greatlakes_w.php |url-status=dead |archive-url=https://web.archive.org/web/20110611015119/http://science.natureconservancy.ca/initiatives/blueprints/greatlakes_w.php |archive-date=June 11, 2011 |title=Great Lakes |website=Nature Conservancy Canada}}</ref> Deforestation in the vicinity of the lake has had many negative impacts,<ref>[[Michael Williams (geographer)|Williams, M.]] 1989. ''Americans and Their Forests: A Historical Geography''. Cambridge: Cambridge University Press.</ref> including loss of forest birds, extinction of native salmon, and increased amounts of sediment flowing into the lake. In some areas, more than 90 percent of the [[forest cover]] has been removed and replaced by agriculture. Certain tree species, such as hemlock, have also been particularly depleted by past logging activity.<ref>Keddy, C.J. 1993. Forest History of Eastern Ontario. A report prepared for the Eastern Ontario Forest Group.</ref> Guidelines for restoration stress the importance of maintaining and restoring forest cover, particularly along streams and wetlands.<ref>Environment Canada. 2004. How Much Habitat is Enough? A Framework for Guiding Habitat Rehabilitation in Great Lakes Areas of Concern. 2nd ed. 81 p.</ref><ref>Keddy, P.A. and C. G. Drummond. 1996. Ecological properties for the evaluation, management, and restoration of temperate deciduous forest ecosystems. Ecological Applications 6: 748–762.</ref>

By the 1960s and 1970s, the increased pollution caused frequent [[algal bloom]]s to occur in the summer.<ref name="Christie, W. J. 1974"/> These blooms killed large numbers of fish, and left decomposing piles of filamentous algae and dead fish along the shores.<ref>Vallentyne, J. R. (1974). The Algal Bowl: Lakes and Man, Miscellaneous Special Publication No. 22. Ottawa, ON: Department of the Environment, Fisheries and Marine Service.</ref>

=== Water pollution ===
Lake Ontario is the most downstream lake of the Great Lakes, so the pollution from all the other lakes flows into it. Lake Ontario was ranked as the most environmentally stressed amongst the five Great Lakes in a 2015 ecological study. Some of the stresses on the lake include excess application of fertilizers in agriculture running into the lake, spillover from obsolete municipal [[sewage systems]], toxic chemicals from industries along the rivers that drain into the lake, and metropolitan drainage from big cities like Toronto, Rochester, and Hamilton.<ref>{{Cite journal |last1=Estepp |first1=Lisa R. |last2=Reavie |first2=Euan D. |date=2015-09-01 |title=The ecological history of Lake Ontario according to phytoplankton |url=https://www.sciencedirect.com/science/article/pii/S0380133015001331 |journal=Journal of Great Lakes Research |language=en |volume=41 |issue=3 |pages=669–687 |doi=10.1016/j.jglr.2015.06.005 |bibcode=2015JGLR...41..669E |issn=0380-1330|hdl=11299/186099 |hdl-access=free }}</ref>

[[Randle Reef]], the westernmost part of Lake Ontario, has been identified as one of the most contaminated areas on Lake Ontario alongside other [[Great Lakes Areas of Concern#List of areas of concern|areas of concern on Great Lakes]]. However, a $150-million cleanup project had begun in 2016 and is expected to be completed by 2025.<ref>{{Cite news |last=Rosas |first=Aura |date=7 September 2023 |title=Final stage of cleaning up contaminated Randle Reef gets underway in Hamilton Harbour |url=https://www.cbc.ca/news/canada/hamilton/randle-reef-cleaning-step-three-1.6958295 |access-date=27 December 2023}}</ref>

==Human history==
The name Ontario is derived from the Huron word ''Ontarí'io'', which is often translated as "great lake".<ref name=":0" /> In Colonial times, the lake was also called ''Cataraqui'', a French spelling of the [[Mohawk language|Mohawk]] ''Katarokwi''.<ref>{{cite web |last1=Murray |first1=Laura |title=Ka'tarohkwi: The Original Swamp Ward? |url=https://swampwardhistory.com/katarokwi-the-original-swamp-ward/ |website=The Swamp Ward and Inner Harbour History Project |date=July 12, 2017 |access-date=Mar 21, 2022}} One translation of the name is "muddy land", or swamp.</ref><ref>{{cite journal |last1=Ikwe |first1=Zoogipon |title=History of Katarokwi |journal=The Queen's University Journal |date=November 13, 2020 |url=https://www.queensjournal.ca/story/2020-11-13/news/history-of-katarokwi/ |access-date=Mar 19, 2022}}</ref> The first archaeologically evidence of humans in the Lake Ontario region dates to circa 11,000 BP. These peoples were mobile foragers who based much of their movement and settlement on the seasonal migrations of caribou, but who also used smaller animals and plant resources.<ref>{{Cite book |last=Storck |first=Peter |title=Journey to the Ice Age: Discovering an Ancient World |publisher=Royal Ontario Museum |year=2004 |location=Toronto, ON}}</ref> These early settlers likely inhabited the lake margins, but those early lake shores are now either far from the current lake representing earlier, higher waters, or submerged under the modern lake, representing periods of lower lake levels. Lake Ontario reached its modern level circa 4000 BP.<ref>{{Cite book |last=Anderson |first=T.W. |title=Quaternary Evolution of the Great Lakes |last2=Lewis |first2=C.F.M. |publisher=Geological Association of Canada |year=1985 |editor-last=Karrow |editor-first=P.F. |location=St. Johns, NL |chapter=Postglacial Water-Level History of the Lake Ontario Basin |editor-last2=Calkin |editor-first2=P.E.}}</ref><ref>{{Cite book |last=Halligan |first=Jessi |title=The Archaeology of Maritime Landscapes |publisher=Springer |year=2011 |editor-last=Ford |editor-first=Ben |location=New York, NY |chapter=Lake Ontario Paleoshorelines and Submerged Prehistoric Site Potential in the Great Lakes}}</ref> The lake was a border between the [[Wyandot people|Huron]] people and the [[Iroquois]] Confederacy in the [[pre-Columbian era]]. In the 17th century, the Iroquois committed genocide against the Huron in southern Ontario and [[Iroquois settlement of the north shore of Lake Ontario|settled the northern shores of Lake Ontario]].<ref>{{cite web | title = Iroquois' destruction of Huronia | publisher = CBC | url = https://www.cbc.ca/history/EPCONTENTSE1EP2CH5PA5LE.html | accessdate = May 12, 2025}}</ref> When the Iroquois withdrew and the [[Anishinaabe]] moved in from the north to southern Ontario, they retained the Iroquois name.{{sfn|Smith|1987|p=10}}

[[File:Iroquois Settlement on the north shore of Lake Ontario 1665-1701.tiff|thumb|left|A map depicting the [[Iroquois settlement of the north shore of Lake Ontario]] during the late-17th century.]]

It is believed the first European to reach the lake was [[Étienne Brûlé]] in 1615. European colonization of Lake Ontario was slow and uneven due to the power and organization of the Haudenosaunee, Wendat, and Ojibwe nations. From 1688 to 1694 the Haudenosaunee largely excluded the French from Lake Ontario.<ref>{{Cite book |last=Pound |first=Arthur |title=Lake Ontario |publisher=Bobbs-Merrill Company |year=1945 |location=New York, NY |pages=9}}</ref>

As was their practice, the French explorers introduced other names for the lake. In 1632 and 1656, the lake was referred to as Lac de St. Louis or Lake St. Louis by [[Samuel de Champlain]] and cartographer [[Nicolas Sanson]] respectively.<ref>[http://www.great-lakes.net/lakes/ref/ontfact.html Lake Ontario Facts and Figures] {{webarchive|url=https://web.archive.org/web/20110312050046/http://www.great-lakes.net/lakes/ref/ontfact.html |date=March 12, 2011 }}. Great-lakes.net (February 28, 2005). Retrieved on November 29, 2011.</ref> In 1660, [[Society of Jesus|Jesuit]] historian [[Francis Creuxius]] coined the name ''Lacus Ontarius''. In a map drawn in the ''Relation des Jésuites'' (1662–1663), the lake bears the legend "Lac Ontario ou des Iroquois" with the name "Ondiara" in smaller type. A French map produced in 1712 (currently in the [[Canadian Museum of History]]<ref>{{cite web |archive-url=https://web.archive.org/web/20080419150617/http://www.civilization.ca/vmnf/popul/coureurs/cartenf.htm |archive-date=April 19, 2008 |title=L'Amérique française en 1712 |url=http://www.civilization.ca/vmnf/popul/coureurs/cartenf.htm |publisher=Canadian Museum of Civilization}}</ref>), created by military engineer [[Jean-Baptiste de Couagne]], identified Lake Ontario as "Lac Frontenac" named after Louis de Buade, Comte de Frontenac et de Palluau. He was a French soldier, courtier, and Governor General of [[New France]] from 1672 to 1682 and from 1689 to his death in 1698.

In the 17th century, reports of an alleged creature named [[Gaasyendietha]], similar to the so-called [[Loch Ness Monster]], being sighted in the lake. The creature is described as large with a long neck, green in colour, and generally causes a break in the surface waves.<ref name=MorningPost>The Morning Post (London, England), Saturday, July 25, 1835; p. 6 "Sea Serpent in Lake Ontario"</ref><ref name=GlasgowHerald>Glasgow Herald (Glasgow, Scotland), Friday, June 28, 1867 "Another Sea Serpent Sensation: A hideous monster discovered in Lake Ontario"</ref><ref>Pinkwater, Daniel. ''The Monster of Lake Ontario''. New York: Houghton Mifflin Publishing, 2010, pp. 46–47.</ref>

A series of trading posts were established by both the British and French, such as [[Fort Frontenac]] in 1673, [[Fort Oswego]] in 1722, and [[Fort Rouillé]] in 1750. As the easternmost and nearest lake to the Atlantic seaboard of Canada and the United States, population centres here are among the oldest in the Great Lakes basin, with [[Kingston, Ontario]], formerly the [[Province of Canada|capital of Canada]], dating to the establishment of Fort Frontenac in 1673.  
[[File:United States sloop of war General Pike, commodore Chauncey, and the British sloop of war Wolf, Sir James Yeo, Preparing for action, September 28, 1813.jpg|thumb|{{USS|General Pike}} and {{HMS|Wolfe|1813|6}} prepare for action on September 28, 1813. The battle was one of several [[Engagements on Lake Ontario|engagements that took place on Lake Ontario]] during the [[War of 1812]].]]
After the [[French and Indian War]], all forts around the lake were under British control. During the [[American Revolution]], the British controlled Lake Ontario from their bases at [[Carleton Island]], [[Navy Hall]], and [[Oswego, New York|Oswego]], allowing them to largely excluded the Americans from the lake.<ref>{{Cite book |last=Smith |first=Arthur Britton |title=Legend of the Lake: The 22-Gun Brig Sloop Ontario |publisher=Quarry Press |year=1997 |location=Kingston, ON}}</ref> The United States took possession of the forts along the American side of the lake at the signing of the [[Jay Treaty]] in 1794. Permanent, non-military European settlement began during the [[American Revolution]] with the influx of [[United Empire Loyalists|Loyalist]] settlers.

Following the American Revolution, sailing commerce slowly returned to Lake Ontario. There was one private commercial vessel, the ''Good Intent'', on the lake in 1788. Several more vessels were launched prior to 1800, primarily by Canadian merchants.<ref>{{Cite book |last=Cruikshank |first=E.A. |title=Ontario Historical Society’s Papers and Records XXIII |publisher=Ontario Historical Society |year=1926 |location=Toronto, ON |pages=6–7 |chapter=Notes on the History of Shipbuilding and Navigation on Lake Ontario up to the Time of the Launching of the Steamship Frontenac, at Ernesttown, Ontario, 7th September, 1816}}</ref> Commerce continued to expand until the [[Embargo Act of 1807|Embargo of 1807]]. There was significant smuggling across Lake Ontario during the embargo.<ref>{{Cite journal |last=Cain |first=Emily |title=Customs Collection and--Duitable Goods: Lake Ontario Ports, 1801-1812 |journal=Fresh Water |volume=2 |issue=2 |pages=22–27}}</ref>

During the War of 1812, the Royal Navy and US Navy operated substantial shipyards at Kingston, Ontario and [[Sackets Harbor, New York|Sackets Harbor]], New York, respectively, and [[Engagements on Lake Ontario|fought in several engagements for control of Lake Ontario]].  The Great Lakes, including Lake Ontario, were largely demilitarized after the [[Rush–Bagot Treaty]] was ratified in 1818. As a result, most of the naval vessels were sold or abandoned.<ref>{{Cite book |title=Coffins of the Brave, Lake Shipwrecks of the War of 1812 |publisher=Texas A&M University Press |year=2014 |editor-last=Crisman |editor-first=Kevin |location=College Station, TX}}</ref><ref>{{Cite book |last=Malcomson |first=Robert |title=Lords of the Lake, the Naval War on Lake Ontario, 1812-1814 |publisher=Naval Institute Press |year=1998 |location=Annapolis, MD}}</ref>

The lake became a hub of commercial activity following the [[War of 1812]] with canal building on both sides of the border and significant sailing and steamer commerce.

Sailing commerce on Lake Ontario was initially significant but declined relative to the other Great Lakes after the mid-19th century as the centers of colonialist agriculture, timbering, and mining moved farther west.<ref>{{Cite book |last=Pound |first=Arthur |title=Lake Ontario |publisher=Bobbs-Merrill Company |year=1945 |location=New York |pages=303–304}}</ref> After the [[Erie Canal]] opened, much of the movement of people and commodities between the East Coast and the Great Lakes circumvented Lake Ontario. [[Oswego, New York|Oswego]] remained an important port on Lake Ontario during this time because the [[Oswego Canal]] allowed shippers to connect to the Erie Canal while avoiding bottlenecks at Buffalo, New York.<ref>{{Cite book |last=Barry |first=James |title=Ships of the Great Lakes |publisher=Thunder Bay Press |year=1996 |location=Holt, MI |pages=107, 116}}</ref> [[Kingston, Ontario|Kingston]], [[Clayton, New York|Clayton]], and [[Oswego, New York|Oswego]] were major 19th century wooden shipbuilding centers on Lake Ontario.<ref>{{Cite journal |last=Alford |first=Harold |title=Shipbuilding Days in Old Oswego, Part III |url=https://inlandseas.nmgl.org/4072293/data |journal=Inland Seas |volume=13 |issue=4 |pages=307–310}}</ref><ref>{{Cite book |last=Brown |first=Jack |title=Simon Johnston and the Ships of Clayton |publisher=River Heritage Books |year=198 |location=Mallorytown, ON |pages=69}}</ref> Oil and coal were important commodities shipped on Lake Ontario through the early 20th century.<ref>{{Cite book |last=Monk |first=Kimberly |title=A Great Lakes Vessel Type: Archaeological and Historical Examination of the Welland Sailing Canal Ship, Sligo, Toronto, Ontario |publisher=East Carolina University |year=2003 |location=Greenville, NC |pages=15, 77}}</ref> In the late 19th and early 20th centuries, a type of scow known as a ''stone hooker'' was in operation on the northwest shore, particularly around [[Port Credit, Ontario|Port Credit]] and [[Bronte, Ontario|Bronte]]. [[Stonehooking]] was the practice of raking flat fragments of Dundas [[shale]] from the shallow lake floor of the area for use in construction, particularly in the growing city of Toronto.<ref>Snider, Charles Henry Jeremiah, Townsend, Robert B. Tales from the Great Lakes. Toronto: Dundurn Press Limited, 1995, pp. 25.</ref>

The ''[[PS Frontenac|Frontenac]]'' was the first steamer on Lake Ontario and the Great Lakes. This ship was launched in September 1816 from Finkle's Point (now [[Loyalist, Ontario|Bath]]) near Kingston, ON. ''Frontenac'' was constructed by two shipbuilders who had worked for the Americans during the War of 1812 and captained by a former Royal Navy sailing master.<ref>{{Cite book |last=Cruikshank |first=E.A. |title=Ontario Historical Society’s Papers and Records XXIII |publisher=Ontario Historical Society |year=1926 |location=Toronto, ON |chapter=Notes on the History of Shipbuilding and Navigation on Lake Ontario up to the Time of the Launching of the Steamship Frontenac, at Ernesttown, Ontario, 7th September, 1816}}</ref><ref name=":02">{{Cite journal |last=Lewis |first=Walter |date=1987 |title=The Frontenac: A Reappraisal |journal=Fresh Water |volume=2 |issue=1 |pages=28–39}}</ref> The Americans at Sackets Harbor launched a smaller steamship, the ''[[Ontario (steamboat)|Ontario]], in'' March 1817.<ref name=":02" /><ref name=":1">{{Cite book |last=Barry |first=James |title=Ships of the Great Lakes |publisher=Thunder Bay Press |year=1996 |location=Holt, MI |pages=59}}</ref>

As bulk cargoes became increasingly important in Great lakes commerce and the number of improved harbors increased, so did propeller ships.<ref name=":1" /><ref name=":2">{{Cite journal |last=Ericson |first=Bernard |date=1969 |title=The Evolution of Great Lakes Ships, Part II – Steam and Steel |journal=Inland Seas |volume=25 |issue=3 |pages=199–212}}</ref> The number of propeller ships exceed the number of side-wheel steamers by circa 1857.<ref>{{Cite journal |last=Odle |first=Thomas |date=1952 |title=The American Grain Trade of the Great Lakes, 1825–1873, Part IV |url=https://inlandseas.nmgl.org/4072039/data |journal=Inland Seas |volume=8 |issue=3 |pages=177–192}}</ref> The ''Vandalia'' was the first propeller ship on the Great Lakes and the second in the United States. Launched at Oswego in 1841, ''Vandalia''{{'}}s propeller was designed by [[John Ericsson]].<ref name=":1" /><ref name=":2" /> Steamer activity peaked in the mid-19th century before competition from railway lines.<ref>{{Cite book |last=Barry |first=James |title=Ships of the Great Lakes |publisher=Thunder Bay Press |year=1996 |location=Holt, MI |pages=145}}</ref><ref>{{Cite book |last=Meinig |first=D.W. |title=Geography of New York State |publisher=Syracuse University Press |year=1966 |editor-last=Thompson |editor-first=John |location=Syracuse, NY |pages=140–171 |chapter=Geography of Expansion, 1785–1855}}</ref>

Iron hull construction developed on Lake Ontario during the mid-19th century but did not become widespread until the early 20th century. The first iron-hulled ship on the Great Lakes, the British paddle-wheel gunboat HMS ''Mohawk'', was launched at Kingston in 1843. The ''Passport'' and the ''Magnet'', both built for the Royal Mail Line, were launched at Kingston in 1846 and at Niagara in 1847, respectively.<ref>{{Cite web |last=USA356-6188 |first=Michigan 49707 |title=PASSPORT (1846, Steamer) |url=https://greatlakeships.org/2899684/data |access-date=2025-05-20 |website=greatlakeships.org |language=en}}</ref><ref>{{Cite web |title=Magnet - Great Lakes Vessel HistoryGreat Lakes Vessel History |url=https://www.greatlakesvesselhistory.com/histories-by-name/m/magnet |access-date=2025-05-20 |website=www.greatlakesvesselhistory.com}}</ref>

===Swims across the lake===
[[File:Marilyn bell plaque 2015.jpg|thumb|A plaque for [[Marilyn Bell]], the first person to swim across the lake.]]
{{as of|2012}}, nearly 50 people have successfully swum across the lake.<ref>{{cite news |author=((CNN Wire Staff)) |work=CNN |url=http://www.cnn.com/2012/08/19/world/americas/canada-teen-swimmer/index.html |title=14-year-old swims solo across Lake Ontario |date=August 20, 2012 |access-date=August 20, 2012 |url-status=live |archive-url=https://web.archive.org/web/20120820040250/http://www.cnn.com/2012/08/19/world/americas/canada-teen-swimmer/index.html |archive-date=August 20, 2012  }}</ref> The first person who accomplished the feat was a Canadian long distance swimmer [[Marilyn Bell]], who did it in 1954 at age 16. Toronto's Marilyn Bell Park is named in her honour. The park opened in 1984 and is east of the spot where Bell completed her swim.<ref>{{cite web |url=https://www.youtube.com/watch?v=-9nnrvJnCss |title=Plaque in Marilyn Bell Park |publisher=[[YouTube]] |access-date=August 21, 2012 |url-status=live |archive-url=https://web.archive.org/web/20131017180721/http://www.youtube.com/watch?v=-9nnrvJnCss |archive-date=October 17, 2013  }}</ref> In 1974, [[Diana Nyad]] became the first person who swam across the lake against the current (from north to south).<ref>{{cite journal |first=Todd |last=Pitock |url=http://www.rd.com/true-stories/inspiring/the-unsinkable-diana-nyad/ |title=The Unsinkable Diana Nyad |journal=[[Reader's Digest]] |issue=November 2011 |access-date=August 20, 2012 |url-status=live |archive-url=https://web.archive.org/web/20130927030926/http://www.rd.com/true-stories/inspiring/the-unsinkable-diana-nyad/ |archive-date=September 27, 2013  }}</ref> On August 28, 2007, 14-year-old Natalie Lambert from Kingston, Ontario, made the swim, leaving Sackets Harbor, New York, and reaching Kingston's Confederation basin less than 24 hours after she entered the lake.<ref>{{cite news|url=http://www.cbc.ca/news/canada/ottawa/kingston-teen-becomes-youngest-to-swim-lake-ontario-1.643621|title=Kingston teen becomes youngest to swim Lake Ontario|work=CBC|date=August 28, 2007|access-date=September 26, 2017|url-status=live|archive-url=https://web.archive.org/web/20160306122420/http://www.cbc.ca/news/canada/ottawa/kingston-teen-becomes-youngest-to-swim-lake-ontario-1.643621|archive-date=March 6, 2016}}</ref> On August 19, 2012, 14-year-old [[Annaleise Carr]] became the youngest person to swim across the lake. She completed the 32-mile (52-km) crossing from Niagara-on-the-Lake to Marilyn Bell Park in just under 27 hours.<ref>{{cite news|last=Alamenciak|first=Tim|title=Annaleise outwits Lake Ontario |url=http://www.thespec.com/news/ontario/article/783488--exhausted-but-jubilant-annaleise-carr-completes-lake-ontario-crossing|url-status=dead|archive-url=https://web.archive.org/web/20120822185502/http://www.thespec.com/news/ontario/article/783488--exhausted-but-jubilant-annaleise-carr-completes-lake-ontario-crossing|archive-date=August 22, 2012|work=The Hamilton Spectator|date=August 20, 2012|access-date=August 20, 2012}}</ref>

==Settlements==
A large [[conurbation]] called the [[Golden Horseshoe]] occupies the lake's westernmost shores, anchored by the cities of Toronto and Hamilton. Ports on the Canadian side include St. Catharines, Oshawa, Cobourg and Kingston, near the St. Lawrence River outlet. Close to 9 million people, or over a quarter of Canada's population, live within the watershed of Lake Ontario. The American shore is largely rural, with the exception of Rochester and the much smaller ports at Oswego and Sackets Harbor. The city of Syracuse is {{convert|40|mi|km}} inland, connected to the lake by the New York State Canal System. Over 2 million people live in Lake Ontario's American watershed.
[[File:Downtown from Ward's Island (11741021983).jpg|thumb|View of Toronto and a frozen Lake Ontario from the [[Toronto Islands]]. Toronto is the largest settlement located along the lake's shoreline.]]
; Ontario, Canada
{{colbegin|colwidth=25em}}
* [[Toronto]]
* [[Mississauga]]
* [[Hamilton, Ontario|Hamilton]]
* [[Burlington, Ontario|Burlington]]
* [[Oshawa, Ontario|Oshawa]]
* [[Kingston, Ontario|Kingston]]
* [[Whitby, Ontario|Whitby]]
* [[Stoney Creek, Ontario|Stoney Creek]]
* [[Grimsby, Ontario|Grimsby]]
* [[Oakville, Ontario|Oakville]]
* [[St. Catharines, Ontario|St. Catharines]]
* [[Port Hope, Ontario|Port Hope]]
* [[Cobourg, Ontario|Cobourg]]
* [[Brighton, Ontario|Brighton]]
* [[Pickering, Ontario|Pickering]]
* [[Ajax, Ontario|Ajax]]
* [[Bowmanville, Ontario|Bowmanville]]
* [[Belleville, Ontario|Belleville]]
* [[Trenton, Ontario|Trenton]]
* [[Niagara-on-the-Lake, Ontario|Niagara-on-the-Lake]]
{{colend}}
; New York, United States
[[File:Ontario Beach Park, Rochester, New York - 20201018 - 02.jpg|thumb|Lake Ontario's beachfront in [[Rochester, New York]]. The city is the largest settlement in New York that is located along the lake's shoreline.]]
{{colbegin|colwidth=25em}}
* [[Rochester, New York|Rochester]]
* [[Greece, New York|Greece]]
* [[Irondequoit, New York|Irondequoit]]
* [[Webster, New York|Webster]]
* [[Oswego, New York|Oswego]]
* [[Fair Haven, New York|Fair Haven]]
* [[Sackets Harbor, New York|Sackets Harbor]]
* [[Cape Vincent, New York|Cape Vincent]]
* [[Three Mile Bay, New York|Three Mile Bay]]
* [[Wilson (village), New York|Wilson]]
* [[Chaumont, New York|Chaumont]]
* [[Olcott, New York|Olcott]]
* [[Sodus Point, New York|Sodus Point]]
{{colend}}

==Islands==
[[File:Amherst Island, Stella Village.jpg|thumb|View of Stella Village on [[Amherst Island]], one of several islands located in the lake.]]
Several islands exist in the lake, the largest of which being [[Wolfe Island (Ontario)|Wolfe Island]]. Nearly all of Lake Ontario's islands are on the eastern and northeastern shores, between the Prince Edward County headland and the lake's outlet at Kingston, underlain by the [[Basement (geology)|basement rock]] found throughout the region. However, there exist several islands in the northwestern portion of the lake. Notable islands include:
{{col div}}
* [[Amherst Island]]
* [[Association Island]]
* [[Big Island (Bay of Quinte)|Big Island]]
* [[Galloo Island]]
* [[Garden Island (Ontario)|Garden Island]]
* [[Grenadier Island, New York|Grenadier Island]]
* [[Little Galloo Island]]
* [[Nicholson Island (Lake Ontario)|Nicholson Island]]
* [[Simcoe Island]]
* [[Toronto Islands]] (an island chain of 15 smaller islands)
* [[Waupoos Island, Ontario|Waupoos Island]]
* [[Wolfe Island (Ontario)|Wolfe Island]]
{{col div end}}

==Navigation==
[[File:St. Lawrence Seaway locks and crossings.png|center|upright=3.0|thumb|Diagram of the Montreal-Lake Ontario portion of the [[Saint Lawrence Seaway]]]]

The [[Great Lakes Waterway]] connects the lake sidestream to the Atlantic Ocean via the Saint Lawrence Seaway and upstream to the other rivers in the chain via the [[Welland Canal]] and to Lake Erie. The [[Trent-Severn Waterway]] for pleasure boats connects Lake Ontario at the Bay of Quinte to [[Georgian Bay]] (Lake Huron) via [[Lake Simcoe]]. The [[Oswego Canal]] connects the lake at Oswego to the [[New York State Canal System]], with outlets to the Hudson River, Lake Erie, and [[Lake Champlain]]. The [[Rideau Canal]], also for pleasure boats, connects Lake Ontario at Kingston to the Ottawa River in downtown [[Ottawa]], Ontario.
[[File:Welland Canal Lock 1 Port Weller.JPG|thumb|Canal Lock 1 at the [[Welland Canal]] in Lake Ontario. The canal forms a part of the [[Great Lakes Waterway]], which connects Lake Ontario with the [[St. Lawrence River]] and other [[Great Lakes]].]]
Several lighthouses exist throughout the lake to help with navigation. Notable historic examples include:
{{col div}}
* [[Braddock Point Light]]
* [[Charlotte-Genesee Lighthouse]]
* [[Gibraltar Point Lighthouse]]
* [[Oswego Harbor West Pierhead Light]]
* [[Presqu'ile Provincial Park|Presqu'ile Lighthouse]]
* [[Selkirk Lighthouse]]
* [[Sodus Point Light]]
* [[Stony Point (Henderson) Light|Stony Point Light]]
* [[Thirty Mile Point Light]]
{{col div end}}
A land-based trail that roughly follows the lake's shoreline also exists, the [[Great Lakes Circle Tour]] and [[Seaway Trail]]. The designated scenic road systems connects all of the Great Lakes and the St. Lawrence River.<ref>[http://www.great-lakes.net/tourism/circletour/ Great Lakes Circle Tour] {{webarchive|url=https://web.archive.org/web/20100725204133/http://www.great-lakes.net/tourism/circletour/ |date=July 25, 2010 }}. Great-lakes.net (July 5, 2005). Retrieved on November 29, 2011.</ref> As the Seaway Trail is posted on the U.S. side only, Lake Ontario is the only of the five [[Great Lakes]] to have no posted bi-national circle tour.

==National marine sanctuary==
[[File:2024 Lake Ontario National Marine Sanctuary map.PNG|thumb|350px|A 2024 map of the [[Lake Ontario National Marine Sanctuary]].]]
The [[Lake Ontario National Marine Sanctuary]] covers {{convert|1,722|sqmi|sqnmi km2|0}} in U.S. waters in southeastern Lake Ontario. Designated on September&nbsp;6, 2024, the [[National Marine Sanctuary|national marine sanctuary]] protects historic [[shipwreck]]s and an area of great cultural, historical, and spiritual importance to the [[Native Americans in the United States|Native American]] peoples of the [[Haudenosaunee Confederacy]]. The [[National Oceanic and Atmospheric Administration]]'s [[Office of National Marine Sanctuaries]] and the [[Government of New York (state)|Government of New York]] jointly administer the sanctuary.<ref>{{Cite web |title=Lake Ontario National Marine Sanctuary |url=https://sanctuaries.noaa.gov/lake-ontario/ |access-date=October 14, 2024 |website=sanctuaries.noaa.gov}}</ref><ref>{{cite web |url=https://sanctuaries.noaa.gov/lake-ontario/celebrate.html |title=Lake Ontario National Marine Sanctuary Designation Ceremony |author=<!--Not stated--> |date=<!--Not stated--> |website=sanctuaries.noaa.gov |publisher=National Oceanic and Atmospheric Administration |access-date=October 14, 2024}}</ref>

==Economic impact==
[[File:Ships in Oshawa Harbour, Fall 2017.jpg|thumb|Cargo ships in Oshawa Harbour.]]
Lake Ontario is the site of several major commercial ports including the [[PortsToronto|Port of Toronto]] and the [[Hamilton-Oshawa Port Authority|Port of Hamilton]]. [[Hamilton Harbour]] is the location of major steel production facilities.

The [[government of Ontario]], which holds the lakebed rights of the Canadian portion of the lake under the Beds of Navigable Waters Act,<ref name=trilliumsco/> does not permit [[wind power]] to be generated offshore.<ref name=tsoffshore>{{cite news |url=https://www.thestar.com/business/economy/2013/02/15/ontarios_offshore_wind_turbine_moratorium_unresolved_two_years_later.html|title=Ontario's off-shore wind turbine moratorium unresolved two years later|first=John|last=Spears|date=February 15, 2013|access-date=September 26, 2017 |work=Toronto Star |url-status=live|archive-url=https://web.archive.org/web/20170926143158/https://www.thestar.com/business/economy/2013/02/15/ontarios_offshore_wind_turbine_moratorium_unresolved_two_years_later.html|archive-date=September 26, 2017}}</ref> In ''[[Trillium Power Wind 1|Trillium Power Wind Corporation]] v. Ontario (Natural Resources)'',<ref name=trilliumsco>{{cite web|url=http://www.canlii.org/en/on/onsc/doc/2012/2012onsc5619/2012onsc5619.html|title=Trillium Power Wind Corporation v. Ontario (Natural Resources), 2012 ONSC 5619 (CanLII)|website=canlii.org|access-date=September 26, 2017|url-status=live|archive-url=https://archive.today/20130829205027/http://www.canlii.org/en/on/onsc/doc/2012/2012onsc5619/2012onsc5619.html|archive-date=August 29, 2013}}</ref> the [[Ontario Superior Court of Justice|Superior Court of Justice]] held Trillium Power—since 2004 an "Applicant of Record" who had invested $35,000 in fees and, when in 2011 the Crown made a policy decision against offshore windfarms, claimed an injury of $2.25&nbsp;billion—disclosed no reasonable cause of action.

The Great Lakes once supported an industrial-scale fishery, with record hauls in 1899; overfishing later blighted the industry.<ref name="glearb">Author unknown (1972). ''The Great Lakes: An Environmental Atlas and Resource Book''. Bi-national (U.S. and Canadian) resource book.</ref> However, only recreational fishing activities exist in the 21st century.

==See also==
{{portal|Lakes}}
*[[Charity Shoal Crater]]
*[[Glacial Lake Admiralty]]
*[[Lake Ontario Waterkeeper]]
*[[List of lakes of Ontario]]

==References==
<references>
<ref name="GLBathOnt">[https://www.ncei.noaa.gov/products/great-lakes-bathymetry National Geophysical Data Center], 1999. Bathymetry of Lake Ontario. National Geophysical Data Center, NOAA. doi:10.7289/V56H4FBH [access date: March 23, 2015].</ref>
<ref name="GLBathEr">[https://www.ncei.noaa.gov/products/great-lakes-bathymetry National Geophysical Data Center], 1999. Bathymetry of Lake Erie and Lake Saint Clair. National Geophysical Data Center, NOAA. doi:10.7289/V5KS6PHK [access date: March 23, 2015]. (only small portion of this map)</ref>
<ref name="GLOBE">National Geophysical Data Center, 1999. [http://www.ngdc.noaa.gov/mgg/topo/gltiles.html Global Land One-kilometer Base Elevation (GLOBE) v.1.] {{webarchive|url=http://archive.wikiwix.com/cache/20110224025742/http://www.ngdc.noaa.gov/mgg/topo/gltiles.html |date=February 24, 2011 }} Hastings, D. and P.K. Dunbar. National Geophysical Data Center, NOAA. doi:10.7289/V52R3PMS [access date: March 16, 2015].</ref>
<ref name="NOAA_GLERL">{{cite web |url=http://www.glerl.noaa.gov/pr/ourlakes/gl_tour.html |title=About Our Great Lakes: Tour |publisher=National Oceanic and Atmospheric Administration (NOAA) – Great Lakes Environmental Research Laboratory (GLERL) |access-date=April 2, 2015 |url-status=dead |archive-url=https://web.archive.org/web/20110505021024/http://www.glerl.noaa.gov/pr/ourlakes/gl_tour.html |archive-date=May 5, 2011  }} Google Earth Great Lakes Tour [http://www.glerl.noaa.gov/pr/pr_images/tour/GreatLakesTour_Merged.kmz GreatLakesTour_Merged.kmz] {{webarchive|url=https://web.archive.org/web/20150105214620/http://www.glerl.noaa.gov/pr/pr_images/tour/GreatLakesTour_Merged.kmz |date=January 5, 2015 }}</ref>
</references>

===Bibliography===
* {{cite journal |first=Gary |last=May |title=The Day the Lake Froze Over |journal=[[Watershed Magazine]] |issue=Winter 2008/2009 |url=http://www.garymay.ca/article18.htm |year=2008 }}
* {{cite book |last=Smith |first=Donald B. |title=Sacred Feather |year=1987 |publisher=[[University of Toronto Press]] |isbn=0-8020-6732-8 }}
* {{cite book |editor-first=John W. |editor-last=Wright |year=2006 |title=The New York Times Almanac |url=https://archive.org/details/newyorktimes200600wrig |url-access=registration |edition=2007 |publisher=[[Penguin Books]] |location = New York, New York | isbn=0-14-303820-6 }}

==External links==
{{Wikivoyage}}
{{commons category|Lake Ontario}}
*{{osmrelation|1206310}}
*[http://www.charts.noaa.gov/OnLineViewer/14820.shtml Lake Ontario NOAA nautical chart #14820 online]
*[https://web.archive.org/web/20000531083545/http://www.epa.gov/glnpo/atlas/index.html EPA's Great Lakes Atlas]
*[http://www.coastwatch.msu.edu/ Great Lakes Coast Watch] {{Webarchive|url=https://web.archive.org/web/20080511230142/http://www.coastwatch.msu.edu/ |date=May 11, 2008 }}
*[http://www.ngdc.noaa.gov/mgg/greatlakes/lakeontario_cdrom/html/gmorph.htm Lake Ontario Bathymetry]
{{Great Lakes}}
{{Lighthouses of Lake Ontario}}

{{Authority control}}

[[Category:Lake Ontario| ]]
[[Category:Lakes of Ontario|Ontario, Lake]]
[[Category:Lakes of New York (state)|Ontario, Lake]]
[[Category:Saint Lawrence Seaway]]
[[Category:Canada–United States border]]
[[Category:International lakes of North America|Ontario]]
[[Category:Great Lakes|*Ontario]]