SIERRA DIABLO. The Sierra Diablo begins twelve miles northeast of Sierra Blanca and extends nineteen miles northeast to its end on the Hudspeth-Culberson county line (its center is at 31°25' N, 104°54' W). The highest elevation in the range rises 6,610 feet above sea level in Culberson County. The Sierra Diablo Wildlife Management Area, in both counties, consists of some 10,991 acres and contains a well-established mule deer population and free-ranging bighorn sheep. Camping is allowed in the wildlife area, although all water and other supplies must be brought in. The Sierra Diablo forms the western flank of the Culberson County salt basin. There rough, rugged terrain and steep canyons are surfaced by shallow, stony soils that support oak, juniper, mesquite, piñon, and grasses; at the higher elevations Douglas fir, aspen, Arizona cypress, maple, ponderosa pine, and madrone can be found.