The Great Basin Divide in the western United States is the ridgeline that separates the Great Basin from the

Pacific Ocean The Pacific Ocean is the largest and deepest of Earth's five Borders of the oceans, oceanic divisions. It extends from the Arctic Ocean in the north to the Southern Ocean, or, depending on the definition, to Antarctica in the south, and is ...

watershed, which completely surrounds it. The Great Basin is the largest set of contiguous endorheic watersheds of

North America North America is a continent in the Northern Hemisphere, Northern and Western Hemisphere, Western hemispheres. North America is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South Ameri ...

, including six entire

USGS The United States Geological Survey (USGS), founded as the Geological Survey, is an government agency, agency of the United States Department of the Interior, U.S. Department of the Interior whose work spans the disciplines of biology, geograp ...

watershed

subregions A subregion is a part of a larger geographical region or continent. Cardinal directions are commonly used to define subregions. There are many criteria for creating systems of subregions; this article is focusing on the United Nations geoscheme ...

. It contains the watersheds of several large prehistoric and still-existing lakes, most notably Lake Bonneville, Lake Lahontan,

Lake Manly Lake Manly was a pluvial lake in Death Valley, California. It forms occasionally in Badwater Basin after heavy rainfall, but at its maximum extent during the so-called "Blackwelder stand," ending approximately 120,000 years before present, the ...

, and the

Salton Sea The Salton Sea is a shallow, landlocked, highly salinity, saline endorheic lake in Riverside County, California, Riverside and Imperial County, California, Imperial counties in Southern California. It lies on the San Andreas Fault within the S ...

. As such, it occupies most of present-day Nevada, about half of Utah, large parts of eastern California and Oregon, and small parts of Idaho, Wyoming, and Baja California. The arid climate of this area ensures that none of the major lake basins are filled to overflowing, and thus no precipitation falling into them reaches the sea. Precipitation falling on the exterior of the Great Basin Divide does (if not evaporated or consumed on the way) reach the Pacific Ocean, through a number of different channels. Roughly speaking, the area to the north and northeast of the Great Basin drains into the

Columbia River The Columbia River (Upper Chinook language, Upper Chinook: ' or '; Sahaptin language, Sahaptin: ''Nch’i-Wàna'' or ''Nchi wana''; Sinixt dialect'' '') is the largest river in the Pacific Northwest region of North America. The river headwater ...

, mostly via the

Snake River The Snake River is a major river in the interior Pacific Northwest region of the United States. About long, it is the largest tributary of the Columbia River, which is the largest North American river that empties into the Pacific Ocean. Begin ...

. Likewise, the area to the south and southeast drains into the

Colorado River The Colorado River () is one of the principal rivers (along with the Rio Grande) in the Southwestern United States and in northern Mexico. The river, the List of longest rivers of the United States (by main stem), 5th longest in the United St ...

, a good part of it via the Green River. The area west of the Great Basin is drained by the Klamath River, the Central Valley of California (

Sacramento Sacramento ( or ; ; ) is the capital city of the U.S. state of California and the seat of Sacramento County. Located at the confluence of the Sacramento and American Rivers in Northern California's Sacramento Valley, Sacramento's 2020 p ...

and San Joaquin Rivers), and various small rivers of southern California and northern Baja California.

References

{{Great Basin watersheds Drainage divides Geography of the United States