The Tonopah Desert is mostly east-west trending, small, approximately 30 mi long, and lies at the plains of low elevation mountains north; the Belmont Mountains are northeast with the Hummingbird Springs Wilderness in its north-northwest. It borders the 'low elevation mountain valley' with the Big Horn Mountains to the west. The Big Horn Mountains Wilderness comprise most of the Big Horn's. The desert is bordered east by other mountain foothills on the west border of the Hassayampa River.