Most U.S. hydropower capacity is in the West

More than half of U.S. hydroelectric capacity for electricity generation is concentrated in Washington, Oregon, and California. In 2014, approximately 30% of total U.S. hydropower was generated in Washington, which is the site of the Grand Coulee Dam, the largest hydroelectric facility in the United States. Although Washington has the most hydroelectric generating capacity of any state, New York has the largest hydroelectric capacity of all states east of the Mississippi River.

Most hydropower is produced at large facilities built by the federal government. The West has many of the largest dams, but there are also smaller facilities operating around the country.

Most dams were not built for power generation

Only a small percentage of dams in the United States produce electricity. Most dams were constructed for irrigation and flood control.