Upper Stillwater Dam and Reservoir, features of the Central Utah Project, Bonneville Unit, are are Rock Creek, about 31 miles northwest of Duchesne, Utah.Recreation management at Upper Stillwater Reservoir is under the jurisdiction of the U.S. Forest Service, Ashley National Forest. The Forest Service can be reached at 435-789-1181. Situated northwest of Mountain Home, Utah, in a timber setting with an 8,170-foot elevation and a surface area of 330 acres. Managed recreation season is June through September with high use on holidays and weekends. Available fish species include rainbow, brown, and brook trout. Tworoose Pass U.S. Geological Service map covers the area. A campground nature trail exists. Reservations are accepted at certain campsites. Fees charged. Some stream fishing below the reservoir.