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 F ...

in southwest

Montana Montana () is a state in the Mountain West division of the Western United States. It is bordered by Idaho to the west, North Dakota and South Dakota to the east, Wyoming to the south, and the Canadian provinces of Alberta, British Columb ...

(east of the Continental Divide). 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 long, in Beaverhead County, in southwestern Montana, United States. It is the last habitat in the contiguous United States for native fluvial Arctic grayling and is ...

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 gr ...

passed the area in 1805. There were also many beavers in the area at the time, but the name does not originate from the animal. In 1805, Captain Meriwether Lewis 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 longest tributary of the

Mississippi River The Mississippi River is the second-longest river and chief river of the second-largest drainage system in North America, second only to the Hudson Bay drainage system. From its traditional source of Lake Itasca in northern Minnesota, it fl ...

. 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