The Flaming Gorge Dam is a concrete-arch dam on the Green River in Utah, in the United States. Built in 1958-1964, the dam is 502 feet (153 m) tall, 1,180 feet (360 m) long, and 131 feet (40 m) thick. It is one of the biggest dams in the United States. Its reservoir, the Flaming Gorge Reservoir, is about 91 miles (146 km) long, and covers 42,000 acres (170 square kilometers). The dam was built for water storage and hydroelectric power, and it produces about 152 megawatts of electricity.