Tongue River Reservoir State Park is a public recreation area located 6 miles north of Decker, Montana, on the western shore of the Tongue River Reservoir.

The 12-mile-long reservoir is an impoundment of the Tongue River.

The state park, occupying 642 acres at an elevation of 3468 feet, offers boating, fishing, camping, swimming, wildlife viewing, and a seasonal marina.

[1] This state park offers a 3,600 acre reservoir that is regularly stocked for fishing.

Management emphases is for crappie, smallmouth bass, northern pike, and walleye.