Big Sandwash Reservoir is located in Duchesne County, Utah. The reservoir is just south of the city of Altamont. From Highway 40 in Duchesne turn North onto 12000 West and then turn left on East River Road then just after the Duchesne River turn back on to 12000 west and keep going North until you hit the reservoir.
Rainbow Trout, Perch, Largemouth Bass, Brown Trout, Smallmouth Bass, and Walleye.
Open to underwater spearfishing for game fish from Jan. 1 through Dec. 31. Unless otherwise noted, you may use spearfishing to take any legal species.
The Reservoir was enlarged in 2007 and treated with Rotenone. Because of this you may have to drive around the reservoir in order to find access. There is some area's that are private property around the reservoir. New camp grounds and access areas are being built currently. Before Perch were illegally introduced this was one of the best bass fisheries in the state.