The earthen dam was constructed in 1937 by the State of Montana, with a height of 97 feet (30 m), and a length of 2,260 feet (690 m) at its crest.

[3] It impounds Red Lodge Creek for irrigation water storage.

The dam is owned and operated by the Montana Department of Natural Resources and Conservation.

The reservoir it creates, Cooney Reservoir, has a normal water surface of 1.3 square miles (3.4 km2), a maximum storage capacity of 24,195 acre-feet (29,844,000 m3), and a normal capacity of 14,000 acre-feet (17,000,000 m3).

[4] Recreation includes boating, camping, hiking, and fishing for walleye and rainbow trout.