In 1971, wild horses and burros were found roaming across 53.8 million acres of Herd Areas (HAs), of which 42.4 million acres were under the BLM's jurisdiction. Today the BLM manages wild horses and burros in subsets of these HAs, known as Herd Management Areas (HMAs) that comprise 31.6 millionacres, of which 26.9 million acres are under BLM management.
The Black Mountain HMA comprises 50,611 acres of public and other land. The HMAs is located in Owyhee County, south of the Snake River between Murphy and US Highway 95 to the west. HMA characteristics include rolling hills and sagebrush steppe. The horses share the HMA with other wildlife, including deer, antelope and upland game birds.
The horses are known to be of excellent size with good conformation and color. This is the result of the influence of released Thoroughbred and Quarter Horse studs to the herds periodically up to 1978. It is also suspected that horses bred for Cavalry Re-Mounts may have also influenced these herds. In addition to the typical colors of bay, brown, and black, the wild horses include many chestnuts, pintos, paints, roans, grays, duns, grullos, and a few Appaloosas.
Appropriate Mangement Levels (AMLs) for wild horses within the Black Mountain and Hardtrigger HMAs are 30-60 and 66-130, respectively (Owyhee RMP, December 1999).