The Feather River is a principal tributary of the Sacramento River, in length, in Northern California in the United States. It drains part of the northern Sierra Nevada and a small portion of the middle of the Sacramento Valley. The river has a rich history of gold mining in the 19th century. It provides water to central and southern California as being the main source of water for the California State Water Project.
The river rises in three separate forks in the Sierra Nevada which unite as arms of the Lake Oroville reservoir in the foothills 5 mi (8 km) northeast of Oroville in eastern Butte County. The combined stream flows generally south across the Sacramento Valley, east of the Sutter Buttes, past Oroville and Yuba City-Marysville and joining the Sacramento River from the north approximately 20 mi (30 km) NNW of Sacramento.
The North Fork rises in Cold Boiling Lake and Rice Creek in Lassen Volcanic National Park, and Buzzard Springs to the south of the Park. It flows southeast through the Lake Almanor reservoir, then southwest through the Sierra Nevada, receiving the East Branch North Fork from the east near Belden. It flows southeast into Butte County, becoming the northern arm of Lake Oroville.
The East Branch North Fork has it headwaters in eastern Plumas County, south of Honey Lake, as Last Chance Creek. The creek flows westward through the Plumas National Forest, through Indian Valley, becoming Indian Creek and the East Branch North Fork. It flows east past Twain and joins the North Fork near Belden.
The Middle Fork rises in southeastern Plumas County in the Sierra Valley southeast of Beckwourth, combining the short North Branch and the Sierra Branch.in an inverted delta. It flows generally northwest through the Sierra Nevada, past Blairsden, then WSW through the Plumas National Forest to become the middle arm of Lake Oroville. Before construction of the Oroville Dam, it joined the South Fork approximately 1 mi (2 km) from the confluence of the North and South forks.
The South Fork rises in the mountains along the Plumas-Sierra county line and flows west southwest, becoming the south arm of Lake Oroville. It formerly received the Middle Fork approximately 1 mile (2 km) upstream from its confluence with the North Fork.