Tongue River Dam

The Tongue River Dam is a dam in Big Horn County, Montana, a few miles north of the Wyoming state border. It impounds the Tongue River, creating the Tongue River Reservoir.

The earthen dam was constructed in the river canyon in 1939, with a height of 91 feet and a length at its crest of 1824 feet. It impounds Montana's north-flowing Tongue River for flood control and irrigation water storage. The dam and reservoir are owned and operated by the Montana Department of Natural Resources and Conservation.

The 12-mile-long riverine reservoir it creates has a normal water surface of 5.5 square miles, a maximum capacity of 150,000 acre-feet, and normal storage of 69,400 acre-feet. Recreation includes boating, fishing for bass, crappie, walleye and northern pike, and camping in the Tongue River Reservoir State Park.