The Sheeprock Mountains also lie adjacent to two other region perimeters. About 15-mi northwest is Dugway and the entrance to the Dugway Proving Ground, on the southeast perimeter of the Great Salt Lake Desert. The northeast flank of the range forms the southwest border of endorheic Rush Valley; Rush Valley, and endorheic Cedar Valley adjacent east, are west of Utah Lake (and Valley), with all three valleys being just south of the Great Salt Lake perimeter region.