earth-fill dam on the Feather River, California, U.S. Completed by the state of California in 1968, it is the highest dam in the United States and one of the highest embankment dams in the world. The dam, 770 feet (235 metres) high and 6,920 feet (2,109 metres) long at its crest, has a volume of about 78,000,000 cubic yards (59,635,000 cubic metres) and forms a reservoir of some 3,500,000 acre-feet (4,300,000,000 cubic metres) capacity. The first and key unit of the Feather River project, which serves extensive areas in central and southern California hundreds of miles distant, Oroville Dam provides irrigation water, flood control, and some three billion kilowatt-hours of power.