American River, c.30 mi/48 km long, formed in N central Calif., by joining of North Fork and South Fork Amer. rivers at Folsom L. reservoir, 20 mi/32 km NE of Sacramento; flows SW through suburban Sacramento, enters Sacramento R. N of downtown Sacramento. North Fork Amer. R. (c.85 mi/137 km long) rises in E Placer co. in Sierra Nevada, near Squaw Peak, 9 mi/14.5 km WNW of Tahoe City, in Tahoe Natl. Forest; flows W, then SW, passes SE of Colfax and through North Fork Reservoir, receives Middle Fork from E 4 mi/6.4 km below dam, then continues past Auburn to Folsom L. reservoir. South Fork Amer. R. (c. 90 mi/145 km long) rises 10 mi/16 km SE of South L. Tahoe in E El Dorado co., in Sierra Nevada E of Pyramid Peak, in El Dorado Natl. Forest; flows W, receives Silver Creek from NE, flows past Coloma (Marshall Gold Discovery State Historical Park is here), turns SW and receives Weber Creek from E before re-entering Folsom L. reservoir. Middle Fork Amer. R. (c.65 mi/105 km) rises in E Placer co., in Sierra Nevada, 8 mi/12.9 km W of Tahoe City at Squaw Peak, about 1 mi/1.6 km S of source of North Fork Amer.; flows generally WSW through French Meadows Reservoir, receives Rubicon R. from SE, then continues, forming Placer-El Dorado co. line, to North Fork Amer. R. 3 mi/4.8 km NE of Auburn. The discovery of gold at Sutter’s Mill along the river in 1848 led to the Calif. gold rush of 1849 and played an important part in U.S. history.
