The park has two units. Isle du Bois Unit is on the south side of Ray Roberts Lake in Denton County. Johnson Branch Unit is on the north side in Denton and Cooke counties. The Ray Roberts Lake/Lake Lewisville Greenbelt Corridor is a 10-mile multi-use trail system that begins at the Ray Roberts Dam and ends at the headwaters of Lake Lewis.
The lake was created to provide water to the cities of Dallas and Denton. Originally known as Aubrey Reservoir, the lake was renamed in 1980 for a former congressman.
Activities include picnicking, camping, hiking, biking, swimming, boating and fishing.