American River

River in north-central California; length 48 km/30 mi. In January 1848, gold was discovered at Sutter's Mill on the South Fork of the American River, sparking the major gold rush that gripped California in 1848–53.

The river's north and south forks flow from the Sierra Nevada northeast of Folsom, where the Folsom Dam (1955) impounds Folsom Lake. The river then flows southwest to the Sacramento River at Sacramento. At Auburn, 24 km/15 mi north-northeast of Folsom, construction of a 207-m/680-ft-high flood control dam began in 1965 but was halted by an earthquake in 1975 and was not resumed.