The river rises in four main forks in the Sierra Nevada which unite as arms of the Lake Oroville reservoir in the foothills northeast of
Oroville in eastern
Butte County. In terms of drainage area, the largest is the North Fork, which drains about 60% of the entire upper Feather River watershed. The Middle Fork is the second largest, draining about 32% of the upper basin. The South Fork and the West Branch are much smaller, each draining less than 5% of the upper basin.
North Fork in the background The
North Fork Feather River begins in Feather River Meadows at the junction of Rice Creek and South Arm Rice Creek, . The names and confluence locations of the streams in this area were changed by the Board on Geographic Names in 1927. USGS
topographic maps, as of 1995, are mislabeled for South Arm, North Arm Rice Creek, Rice Creek and North Fork Feather River. Rice Creek, labeled North Arm Rice Creek on USGS topo maps, flows south from its source at Cold Boiling Lake, , in
Lassen Volcanic National Park, through Crumbaugh Lake, and south to join the South Arm Rice Creek, forming the North Fork Feather River.
East Branch The East Branch is one of the major tributaries of the Feather River system. It originates at , at the confluence of
Indian Creek and
Spanish Creek. Indian Creek is another long and important tributary, flowing from its source at , on the south slopes of Diamond Mountain, south and west, through Indian Valley and north of American Valley. Impounded at
Antelope Dam, Indian Creek then joins Spanish Creek to form the East Branch North Fork Feather River. The longest tributary of Indian Creek is Last Chance Creek, which rises in eastern Plumas County at , south of
Honey Lake, and flows generally west, joining Indian Creek at the western end of Genesee Valley. From its source at the Indian and Spanish Creeks confluence, the East Branch North Fork flows west past
Twain and joins the North Fork near Belden. The East Branch's main stem length is about . Indian Creek is about long, and Last Chance Creek is about long. The East Branch's most distant headwater is Last Chance Creek's source. The total length from the mouth of the East Branch to the source of Last Chance Creek is about . It is formed by the joining of a number of tributaries that merge in an
inverted river delta wetland with a complex network of irrigation ditches and drains called the Sierra Valley Channels. A number of creeks merge in the Sierra Valley, the longest of which is Little Last Chance Creek, which originates at and flows south through Frenchman Lake and Last Chance Valley to the Sierra Valley, where it divides into two
distributary channels. Other tributaries that join to form the Middle Fork in the Sierra Valley include Carman Creek, Fletcher Creek, Turner Creek, Berry Creek, Hamlin Creek, Sierraville Creek, and Smithneck Creek. It heads on the southwest slope of Pilot Peak, just north of Gibsonville Ridge and Bunker Hill Ridge. It flows west and southwest to
Little Grass Valley Reservoir, an impoundment created by
Little Grass Valley Dam. Below the dam the South Fork flows southwest between Mooreville Ridge and Lumpkin Ridge and enters Butte County. Just before entering Lake Oroville the Ponderosa Diversion Dam impounds the South Fork in the Ponderosa Reservoir. Below the dam the river becomes the south arm of Lake Oroville.
West Branch The Another diversion dam on the West Branch Feather River near
Magalia, called the Magalia 73 Dam, conveys water into the Upper Miocene Canal, which runs to Kunkle Reservoir and the Lime Saddle Powerhouse on Lake Oroville. From the powerhouse water is carried by the Middle Miocene Canal to the Coal Canyon Powerhouse and on into the
Oroville–Thermalito Complex. The Miocene Canal and Lime Saddle Powerhouse are part of the DeSabla Regional Bundle of hydroelectric facilities operated by the
Pacific Gas and Electric Company. The West Branch Feather River flows by
Stirling City and is joined by Big Kimshew Creek and the Little West Fork West Branch Feather River. Concow Creek, flowing southwest from Concow Reservoir, joins just before the West Branch empties into the northwest arm of Oroville Lake, near
Paradise. ==Drainage basin==