The Bureau of Land Management estimates that approximately 31,500 horses and 5,800 burros are roaming BLM-managed rangelands in 10 Western states based on the latest data available, compiled as of September 28, 2012. Wild horses and burros have virtually no natural predators and their herd sizes can double about every four years. As a result, the BLM removes thousands of animals from the range each year to control herd sizes. The estimated current free-roaming population exceeds by 11,000 the number BLM has determined can exist in balance with other public rangeland resources and uses. Off the range, there are more than 47,000 other wild horses and burros that are fed and cared for at BLM short-term corrals and long-term pastures. These Mustangs are awaiting adoption.

The Mustang Heritage Foundation works with the Bureau of Land Management to offer wild horses for adoption through MHF training and adoption programs. The wild horses available during the Mustang Million adoption-auctions will range in age from yearlings to 6-year-olds and will include both mares and geldings in a variety of sizes and colors. Various herd management areas will be represented. For more information on the Bureau of Land Management and the horse characteristics represented in different herd management areas, visit