100th meridian west

The meridian 100° west of the Prime Meridian of Greenwich is a line of longitude 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 and humid subtropical climates in the east, and as such roughly connotes the regions of the 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:

Co-ordinates	Country, territory or sea	Notes
	Arctic Ocean
		Nunavut — Meighen Island
	Peary Channel
		Nunavut — Ellef Ringnes Island
	Unnamed waterbody
		Nunavut — Berkeley Islands and Bathurst Island
	Parry Channel
		Nunavut — Prince of Wales Island
	M'Clintock Channel
	Larsen Sound	Passing just east of Gateshead Island, Nunavut, (at )
	Victoria Strait
		Nunavut — Royal Geographical Society Islands
	Queen Maud Gulf	Passing just east of Hat Island, Nunavut, (at )
		Nunavut Manitoba — from , passing just west of Brandon
		North Dakota South Dakota — from Nebraska — from Kansas — from Oklahoma — from Texas / Oklahoma border — from Texas — from
		Coahuila Nuevo León — from Tamaulipas — from San Luis Potosí — from Tamaulipas — from San Luis Potosí — from Guanajuato — from Querétaro — from State of Mexico — from Guerrero — from , passing just west of Acapulco
	Pacific Ocean
	Southern Ocean
	Antarctica	Unclaimed territory

United States

File:100th meridian US.svg

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

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

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 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 (north of about 37°N) and humid subtropical (south of about 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.

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, 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."

See also

• Rain follows the plow

External links

• https://www.earthmagazine.org/article/dividing-line-past-present-and-future-100th-meridian