[3] With the Red Rock River included in its length, the river stretches another 70 miles (110 km), for a total length of 139 miles (224 km), one of the more significant drainages of south-western Montana.

This rock formation was recognized by Sacajawea when the Lewis and Clark Expedition passed the area in 1805.

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.

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.