The American River (Río de los Americanos) is a -long river in California that runs from the Sierra Nevada mountain range to its confluence with the Sacramento River in downtown Sacramento. Via the Sacramento River, it is part of the San Francisco Bay watershed. This river is fed by the melting snowpack of the Sierra Nevada and its many headwaters and tributaries, including the North Fork American River, the Middle Fork American River, and the South Fork American River.
The American River is known for the discovery of gold at Sutter's Mill in Coloma in 1848 that started the California Gold Rush and contributed to the initial large-scale settlement of California by European immigrants. Today, the river still has high quality water, and it is the main source of drinking water for Sacramento. This river is dammed extensively for irrigation, flood control, and hydroelectric power. The American River watershed supports Mediterranean, temperate, and montane ecosystems, and it is the home of a diverse array of fish and wildlife.
The Maidu, Miwok, Nisenan, and Wintun peoples have inhabited the American River area near present-day Sacramento for at least 5,000 years before Spaniards and colonial Americans arrived in the region; human habitation in what some consider present-day Northern California is believed to date back as far as 12,000 years. These tribes have utilized the vast amount of resources of the American River for shelter, clothes, baskets, and other goods. Europeans and their descendants arrived in the late 18th century. The Nisenan call the river Kum Sayo, meaning 'roundhouse river'.
Spanish explorer Gabriel Moraga named the river Rio de las Llagas (River of Wounds) when he passed through the area in the early 1800s, perhaps due to hostile relations with local native peoples. Another member of the expedition recorded the name as Rio de los Lagos (River of the Lakes) which may or may not have been an error, as in those times the area of the Central Valley surrounding the American River was home to vast marshes, which would have given the river the appearance of a series of lakes.