American River
The North Fork is the longest tributary of the American River, at . It begins at an elevation of about near Lake Tahoe in Placer County at Mountain Meadow Lake, just northeast of Granite Chief and immediately due west of Squaw Valley Ski Resort. It flows westward through remote wilderness areas.
Middle Fork American River
The main stem of the river begins along the Sierra Crest, on the south flank of Granite Chief near Squaw Valley Ski Resort west of Lake Tahoe. It flows west then southwest into French Meadows Reservoir, which is impounded by the L.L. Anderson Dam. Below the dam the Middle Fork enters a rugged and inaccessible canyon more than deep. About downstream, the Middle Fork flows into the Ralston Afterbay, where it is joined from the east by the Rubicon River. Directly below this point, the North Fork of the Middle Fork American River joins from the north. The Middle Fork then flows southwest, past Foresthill, through the Auburn State Recreation Area, and into the North Fork directly below the Foresthill Bridge and above Highway 193. Below this confluence the North Fork flows a further to the Folsom Lake reservoir above Sacramento. Although nominally a tributary of the North Fork, the Middle Fork has a greater flow and drains a much larger watershed of .