The Beaverhead River is an approximately tributary of the

Jefferson River The Jefferson River is a tributary of the Missouri River, approximately long, in the U.S. state of Montana. The Jefferson River and the Madison River form the official beginning of the Missouri at Missouri Headwaters State Park near Three Fo ...

in southwest

Montana Montana ( ) is a landlocked U.S. state, state in the Mountain states, Mountain West subregion of the Western United States. It is bordered by Idaho to the west, North Dakota to the east, South Dakota to the southeast, Wyoming to the south, an ...

(east of the

Continental Divide A continental divide is a drainage divide on a continent such that the drainage basin on one side of the divide feeds into one ocean or sea, and the basin on the other side either feeds into a different ocean or sea, or else is endorheic, not ...

). It drains an area of roughly . The river's original headwaters, formed by the confluence of the Red Rock River and Horse Prairie Creek, are now flooded under Clark Canyon Reservoir, which also floods the first of the river. The Beaverhead then flows through a broad valley northward to join the

Big Hole River The Big Hole River is a tributary of the Jefferson River, approximately 153 miles (246 km) long, in Beaverhead County, Montana, Beaverhead County, in southwestern Montana, United States. It is the last habitat in the contiguou ...

and form the Jefferson River. With the Red Rock River included in its length, the river stretches another , for a total length of , one of the more significant drainages of south-western Montana. The name of the Beaverhead originates from Beaverhead Rock on the middle river. This rock formation was recognized by Sacajawea when the

Lewis and Clark Expedition The Lewis and Clark Expedition, also known as the Corps of Discovery Expedition, was the United States expedition to cross the newly acquired western portion of the country after the Louisiana Purchase. The Corps of Discovery was a select gro ...

passed the area in 1805. There were also many

beaver Beavers (genus ''Castor'') are large, semiaquatic rodents of the Northern Hemisphere. There are two existing species: the North American beaver (''Castor canadensis'') and the Eurasian beaver (''C. fiber''). Beavers are the second-large ...

s in the area at the time, but the name does not originate from the animal. In 1805, Captain

Meriwether Lewis Meriwether Lewis (August 18, 1774 – October 11, 1809) was an American explorer, soldier, politician, and public administrator, best known for his role as the leader of the Lewis and Clark Expedition, also known as the Corps of Discovery, with ...

traveled up the Jefferson and Beaverhead first, but when the rest of the expedition came, a sign Lewis had left at the confluence of the Beaverhead and Big Hole telling them to follow the Beaverhead had been cut down by a beaver, and the expedition traveled up the Big Hole instead. As a result, the swifter current of the Big Hole swamped two of their canoes before they could travel back down to the confluence. Together with the Red Rock River, the Beaverhead forms the uppermost headwaters of the

Missouri River The Missouri River is a river in the Central United States, Central and Mountain states, Mountain West regions of the United States. The nation's longest, it rises in the eastern Centennial Mountains of the Bitterroot Range of the Rocky Moun ...

, the longest tributary of the

Mississippi River The Mississippi River is the main stem, primary river of the largest drainage basin in the United States. It is the second-longest river in the United States, behind only the Missouri River, Missouri. From its traditional source of Lake Ita ...

. The river is a Class I water from the Clark Canyon Dam to its confluence with the Jefferson River for the purposes of public access for recreational purposes.Stream Access in Montana

References

{{authority control Rivers of Montana Rivers of Beaverhead County, Montana Bodies of water of Madison County, Montana

See also

References