Three Forks description
The passage of the river from the Gates of the Mountains to the three forks takes in the Townsend and Missouri River Valley areas. The upriver passage in the Helena vicinity was maddeningly slow for the Corps of Discovery. On July 22, Sacagawea recognized the white clay banks east of present day Winston, Montana. In her youth, her people visited the banks to gather clay for pigment.
Beginning on the South end of Canyon Ferry Reservoir to the Toston Dam, Lewis and Clark set up nine campsites along this short distance in their travels between July 21 and July 25. Those sites were located near present day Canyon Ferry Dam, a site 2 3/4 miles above Beaver Creek, an island below Bedford and a site near Dry Creek south of Townsend.
Entries in their journals refer to Onion Island, Crimson Bluffs, York's Island, Fine Bold Springs, and Little Gates of the Mountains. On July 24th, Captain Lewis referred to the "adjacent mountains" -- these are the Big Belts to the east and to the west is the Elkhorns -- now part of the Helena National Forest.