Dworshak Dam is a concrete gravity dam in the western United States, on the North Fork Clearwater River in Clearwater County, Idaho. The dam is located approximately four miles (6 km) northwest of Orofino and impounds the Dworshak Reservoir for flood control and hydroelectricity generation. With a height of 717 feet (219 m), Dworshak is the third tallest dam in the United States and the tallest straight-axis concrete dam in the Western Hemisphere. Lacking fish ladders, Dworshak Dam blocks fish passage and completely extirpated anadromous fish migration into the upper reaches of the North Fork Clearwater River and its tributaries in Idaho.Construction of the dam by the U.S. Army Corps of Engineers (USACE) began in 1966 and was completed in 1973.