| Tongue River Reservoir | |
|---|---|
 Tongue River Dam | |
  Tongue River Reservoir | |
| Location | Big Horn County, Montana |
| Coordinates | 45°03′38″N106°47′24″W / 45.06056°N 106.79000°W [1] |
| Lake type | Reservoir |
| Primary inflows | Tongue River |
| Primary outflows | Tongue River |
| Basin countries | United States |
| Max. length | 5.5 miles (8.9 km) |
| Max. width | 1.1 miles (1.8 km) |
| Surface area | 3,700 acres (1,500 ha) |
| Water volume | 79,071 acre-feet (97,533,000 m3) [2] |
| Surface elevation | 4,222 feet (1,287 m) [1] |
The Tongue River Dam (National Inventory of Dams ID MT00002) is a dam in Big Horn County, Montana, United States, 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 (28 m) and a length at its crest of 1,824 feet (556 m). [2] 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 (19 km) riverine reservoir it creates has a normal water surface of 5.5 square miles (14 km2), a maximum capacity of 150,000 acre-feet (190,000,000 m3), and normal storage of 69,400 acre-feet (85,600,000 m3). [2] Recreation includes boating, fishing for bass, crappie, walleye and northern pike, [3] and camping in the Tongue River Reservoir State Park. [4] For white-water rafters, the Tongue is a Class I river from the Dam downstream (northward) to its confluence with the Yellowstone River. [5]
