View source for 100th meridian west

{{Short description|Line of longitude}}

{{Location map-line|lon=-100}}
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The '''meridian 100° west''' of the [[Prime Meridian]] of [[Greenwich]] is a line of [[longitude]]<ref>{{cite web |title=What is longitude? |url=https://oceanservice.noaa.gov/facts/longitude.html |website=oceanservice.noaa.gov |access-date=30 June 2025 |language=en}}</ref> that extends from the [[North Pole]] across the [[Arctic Ocean]], [[North America]], the [[Pacific Ocean]], the [[Southern Ocean]], and [[Antarctica]] to the [[South Pole]]. The 100th meridian west forms a [[great circle]] with the [[80th meridian east]].

In the United States, this meridian roughly marks the boundary between the [[semi-arid climate]] in the west and the [[humid continental climate|humid continental]] and [[humid subtropical climate]]s in the east, and as such roughly connotes the regions of the [[Eastern United States|Eastern]] and the [[Western United States]].   

==From Pole to Pole==
Starting at the [[North Pole]] and heading south to the [[South Pole]], the 100th meridian west passes through:

:{| class="wikitable plainrowheaders"
! scope="col" width="130" | Co-ordinates
! scope="col" | Country, territory or sea
! scope="col" | Notes
|-
| style="background:#b0e0e6;" | {{Coord|90|0|N|100|0|W|type:waterbody|name=Arctic Ocean}}
! scope="row" style="background:#b0e0e6;" | [[Arctic Ocean]]
| style="background:#b0e0e6;" |
|-
| {{Coord|80|6|N|100|0|W|type:country|name=Canada}}
! scope="row" | {{CAN}}
| [[Nunavut]] — [[Meighen Island]]
|-
| style="background:#b0e0e6;" | {{Coord|79|52|N|100|0|W|type:waterbody|name=Peary Channel}}
! scope="row" style="background:#b0e0e6;" | [[Peary Channel]]
| style="background:#b0e0e6;" |
|-
| {{Coord|78|44|N|100|0|W|type:country|name=Canada}}
! scope="row" | {{CAN}}
| [[Nunavut]] — [[Ellef Ringnes Island]]
|-
| style="background:#b0e0e6;" | {{Coord|77|48|N|100|0|W|type:waterbody}}
! scope="row" style="background:#b0e0e6;" | Unnamed waterbody
| style="background:#b0e0e6;" |
|-
| {{Coord|76|45|N|100|0|W|type:country|name=Canada}}
! scope="row" | {{CAN}}
| [[Nunavut]] — [[Berkeley Islands]] and [[Bathurst Island (Canada)|Bathurst Island]]
|-
| style="background:#b0e0e6;" | {{Coord|74|59|N|100|0|W|type:waterbody|name=Parry Channel}}
! scope="row" style="background:#b0e0e6;" | [[Parry Channel]]
| style="background:#b0e0e6;" |
|-
| {{Coord|73|57|N|100|0|W|type:country|name=Canada}}
! scope="row" | {{CAN}}
| [[Nunavut]] — [[Prince of Wales Island (Nunavut)|Prince of Wales Island]]
|-
| style="background:#b0e0e6;" | {{Coord|71|52|N|100|0|W|type:waterbody|name=M'Clintock Channel}}
! scope="row" style="background:#b0e0e6;" | [[M'Clintock Channel]]
| style="background:#b0e0e6;" |
|-
| style="background:#b0e0e6;" | {{Coord|70|35|N|100|0|W|type:waterbody|name=Larsen Sound}}
! scope="row" style="background:#b0e0e6;" | [[Larsen Sound]]
| style="background:#b0e0e6;" | Passing just east of [[Gateshead Island]], [[Nunavut]], {{CAN}} (at {{Coord|70|35|N|100|9|W|type:isle|name=Gateshead Island}})
|-
| style="background:#b0e0e6;" | {{Coord|69|58|N|100|0|W|type:waterbody|name=Victoria Strait}}
! scope="row" style="background:#b0e0e6;" | [[Victoria Strait]]
| style="background:#b0e0e6;" |
|-
| {{Coord|69|3|N|100|0|W|type:country_region:CA-NU|name=Canada}}
! scope="row" | {{CAN}}
| [[Nunavut]] — [[Royal Geographical Society Island]]s
|-
| style="background:#b0e0e6;" | {{Coord|68|57|N|100|0|W|type:waterbody|name=Queen Maud Gulf}}
! scope="row" style="background:#b0e0e6;" | [[Queen Maud Gulf]]
| style="background:#b0e0e6;" | Passing just east of [[Hat Island (Victoria Strait)|Hat Island]], [[Nunavut]], {{CAN}} (at {{Coord|68|18|N|100|2|W|type:isle|name=Hat Island}})
|-valign="top"
| {{Coord|67|50|N|100|0|W|type:country_region:CA|name=Canada}}
! scope="row" | {{CAN}}
| [[Nunavut]]<br/> [[Manitoba]] — from {{Coord|60|0|N|100|0|W|type:adm1st|name=Manitoba}}, passing just west of [[Brandon, Manitoba|Brandon]]
|-valign="top"
| {{Coord|49|0|N|100|0|W|type:adm1st_region:US-ND|name=United States (North Dakota)}}
! scope="row" | {{USA}}
| [[North Dakota]]<br/> [[South Dakota]] — from {{coord|45|56|N|100|0|W|type:adm1st_region:US-SD|name=South Dakota}}<br/> [[Nebraska]] — from {{coord|43|0|N|100|0|W|type:adm1st_region:US-NE|name=Nebraska}}<br/> [[Kansas]] — from {{coord|40|0|N|100|0|W|type:adm1st_region:US-KS|name=Kansas}}<br/> [[Oklahoma]] — from {{coord|37|0|N|100|0|W|type:adm1st_region:US-OK|name=Oklahoma}}<br/> [[Texas]] / [[Oklahoma]] border — from {{coord|36|30|N|100|0|W|type:adm1st_region:US|name=Texas / Oklahoma border}}<br/> [[Texas]] — from {{coord|34|34|N|100|0|W|type:adm1st_region:US-TX|name=Texas}}
|-valign="top"
| {{Coord|28|0|N|100|0|W|type:country_region:MX|name=Mexico}}
! scope="row" | {{MEX}}
| [[Coahuila]]<br/> [[Nuevo León]] — from {{coord|27|37|N|100|0|W|type:adm1st|name=Nuevo León}}<br/> [[Tamaulipas]] — from {{coord|23|24|N|100|0|W|type:adm1st|name=Tamaulipas}}<br/> [[San Luis Potosí]] — from {{coord|23|10|N|100|0|W|type:adm1st|name=San Luis Potosí}}<br/> Tamaulipas — from {{coord|22|54|N|100|0|W|type:adm1st|name=Tamaulipas}}<br/> San Luis Potosí — from {{coord|22|50|N|100|0|W|type:adm1st|name=San Luis Potosí}}<br/> [[Guanajuato]] — from {{coord|21|30|N|100|0|W|type:adm1st|name=Guanajuato}}<br/> [[Querétaro]] — from {{coord|21|12|N|100|0|W|type:adm1st|name=Querétaro}}<br/> [[State of Mexico]] — from {{coord|20|6|N|100|0|W|type:adm1st|name=State of Mexico}}<br/> [[Guerrero]] — from {{coord|18|35|N|100|0|W|type:adm1st|name=Guerro}}, passing just west of [[Acapulco]]
|-
| style="background:#b0e0e6;" | {{Coord|16|54|N|100|0|W|type:waterbody|name=Pacific Ocean}}
! scope="row" style="background:#b0e0e6;" | [[Pacific Ocean]]
| style="background:#b0e0e6;" |
|-
| style="background:#b0e0e6;" | {{Coord|60|0|S|100|0|W|type:waterbody|name=Southern Ocean}}
! scope="row" style="background:#b0e0e6;" | [[Southern Ocean]]
| style="background:#b0e0e6;" |
|-
| {{Coord|71|55|S|100|0|W|type:country_region:AQ|name=Antarctica}}
! scope="row" | [[Antarctica]]
| [[List of Antarctic territorial claims|Unclaimed territory]]
|-
|}

==United States==
[[File:100th meridian US.svg|thumb|left|Part of the border between [[Texas]] and [[Oklahoma]] is defined by the 100th meridian west]]
[[File:Directors of the Union Pacific Railroad on the 100th meridian approximately 250 miles west of Omaha, Nebr. Terr. The tra - NARA - 530892.jpg|thumb|350px|Directors of the [[Union Pacific Railroad]] gather on the meridian in the [[Nebraska Territory]] at what is now [[Cozad, Nebraska]], in 1866]]
[[File:Sign at the 100th meridian on U.S. Highway 30 in Cozad, Nebraska.jpg|250px|right|thumb|Sign marking the 100th meridian in [[Cozad, Nebraska]]; photograph taken 138 years after the preceding photograph in October 2004]]

In the [[United States]] the meridian 100° west of Greenwich forms the eastern border of the [[Texas panhandle]] with [[Oklahoma]] (which traces its origin to the [[Adams-Onís Treaty]] in 1819 which settled the border between [[New Spain]] and the United States between the [[Red River of the South|Red River]] and [[Arkansas River]]).  [[Dodge City, Kansas]] lies exactly at the intersection of the Arkansas River and the 100th meridian.

As first noted by [[John Wesley Powell]] in the 1870s, there is a big difference in rainfall by the different sides of the meridian. In the central [[Great Plains]], it roughly marks the western boundary of the normal reach of moist air from the [[Gulf of Mexico]], and the approximate boundary (although some areas do push the boundary slightly farther east) between the [[semi-arid climate]] to the west and the [[humid continental climate|humid continental]] (north of about [[37th parallel north|37°N]]) and [[humid subtropical climate|humid subtropical]] (south of about [[37th parallel north|37°N]]) climates to the east. West of the meridian, raising livestock is much more economically important than east of it, and what [[agriculture]] does exist relies heavily on irrigation. Historically, the meridian has often been taken as a rough boundary between the eastern and western United States. White settlement, spreading westward after the [[American Civil War]], settled the area around this meridian during the 1870s.{{cn|date=August 2024}}

A sign across [[U.S. Highway 30]] in [[Cozad, Nebraska]], marks the place where the 100th meridian intersects with the routes of the [[Oregon Trail]], [[Pony Express]], [[first transcontinental railroad (North America)|transcontinental railroad]], and the [[Lincoln Highway]].

==In popular culture==
The song "[[At the Hundredth Meridian]]" by [[The Tragically Hip]] is about the 100th meridian west, specifically in Canada, and how it has traditionally been considered "where the [[Great Plains]] begin."<ref>{{cite web|last=Krajick|first=Kevin|title=The 100th Meridian, Where the Great Plains Begin, May Be Shifting|date=11 April 2018 |url=https://news.climate.columbia.edu/2018/04/11/the-100th-meridian-where-the-great-plains-used-to-begin-now-moving-east/|publisher=Columbia Climate School|accessdate=September 8, 2023}}</ref>

{{Long-seq|3|west}}

==See also==
*[[Rain follows the plow]]

==References==
{{Reflist}}

==External links==
* https://www.earthmagazine.org/article/dividing-line-past-present-and-future-100th-meridian

{{geographical coordinates|state=collapsed}}

{{DEFAULTSORT:100th Meridian West}}
[[Category:Meridians (geography)|w100 meridian west]]
[[Category:Borders of Oklahoma]]
[[Category:Borders of Texas]]