The Owyhee Mountains are a mountain range in Owyhee County, Idaho and Malheur County, Oregon. Mahogany Mountain and the associated volcanic craters of the Lake Owyhee volcanic field are in the Owyhee Mountains of Oregon just east of the Owyhee Reservoir on the Owyhee River. The southeastern end of the range including the old mining area west of Silver City is referred to as the Silver City Range.