Wild horses in the United States are free-roaming, unbranded horses and burros managed by the federal government. These animals, often referred to as mustangs, are descendants of once-domesticated horses that either escaped or were released into the wild centuries ago. While not truly “wild” in the sense of never having been domesticated, they live without human intervention.
Geographic Distribution Across the United States
Wild horses are primarily found across the vast, open rangelands of the Western United States. Their populations are concentrated in ten Western states: Arizona, California, Colorado, Idaho, Montana, Nevada, New Mexico, Oregon, Utah, and Wyoming. Nevada is home to a significant portion of the total wild horse population, with more than half residing there. These areas typically consist of expansive federal lands. In 2019, the estimated on-range wild horse population exceeded 88,090 animals.
Federal Management and Designated Herd Areas
The Bureau of Land Management (BLM) is the primary federal agency responsible for managing wild horse and burro populations on public lands. This responsibility stems from the Wild Free-Roaming Horses and Burros Act of 1971. This legislation declared these animals “living symbols of the historic and pioneer spirit of the West” and mandated their protection. The Act established specific, legally designated areas known as Herd Management Areas (HMAs) where wild herds are allowed to exist. These HMAs represent areas where wild horses and burros were found when the Act was passed.
The BLM manages these HMAs to ensure the health of the herds and the rangelands. Horses found outside these designated areas are subject to removal. The management framework aims to balance the needs of the wild horses and burros with other public land uses, such as livestock grazing and wildlife habitat. This structure defines where these animals are managed.
Conservation and Population Management
Several strategies manage wild horse populations. One method is the gather, or roundup, where horses are removed from the range. These gathered animals are then offered for adoption through the Wild Horse and Burro Adoption and Sale Program.
To control population growth, fertility control programs are also utilized. These often involve administering a darted vaccine that temporarily prevents conception in mares. These efforts aim to manage herd sizes to align with the land’s capacity to support them, known as the Appropriate Management Level (AML). This helps ensure the long-term sustainability of wild horse populations.