Oroville is the county seat of Butte County, California, United States. The population was 15,506 at the 2010 census, up from 13,004 in the 2000 census. Oroville is considered the gateway to Lake Oroville and Feather River recreational areas. The city of Oroville has recently annexed two locations in South Oroville, areas A and B, which have a combined population of 2,725 people. The U.S. Census Bureau estimated the population of the city to be 17,996 as of January 1, 2016, up 1,908 people or 11.9 percent since 2010. The Berry Creek Rancheria of Maidu Indians of California is headquartered here.

Oroville is located off of State Route 70, and is in close proximity to State Route 99, which connects Butte County with Interstate 5. Chico, California is located about 25 minutes north of the city, and Sacramento lies about an hour south.

Oroville is situated at the base of the foothills on the banks of the Feather River where it flows out of the Sierra Nevada onto the flat floor of the Sacramento Valley. It was established as the head of navigation on the Feather River to supply gold miners during the California Gold Rush.

The town was originally called "Ophir City", but the name was changed to Oroville when the first post office opened in 1854 ("oro" is "gold" in Spanish). The City Of Oroville was incorporated on January 3, 1906.

Gold was found at Bidwell Bar, one of the first gold mining sites in California, bringing thousands of prospectors to the Oroville area seeking riches. Now inundated by the waters of enormous Lake Oroville, which was filled in 1968, Bidwell Bar is memorialized by the Bidwell Bar Bridge, an original remnant from the area and the first suspension bridge in California (California Historical Landmark #314). In the early 20th century the Western Pacific Railroad completed construction of the all-weather Feather River Canyon route through the Sierra Nevadas giving it the nickname of "The Feather River Route". Oroville would serve as an important stop for the famous California Zephyr during its 20-year run. In 1983, this became a part of the Union Pacific Railroad as their Feather River Canyon Subdivision. A major highway, State Route 70, roughly parallels the railroad line winding through the canyon.

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