Free-roaming horse populations exist in Arizona, though their terminology and legal status are complex. These groups of horses are an iconic part of the Western landscape, representing a living connection to the state’s long history. Their management is constantly debated, balancing the preservation of the horses with the ecological health of the fragile desert and riparian environments they inhabit.
Defining Arizona’s Feral Horse Populations
The horses roaming Arizona’s public lands are technically classified as “feral,” not truly “wild.” True wild horses, those never domesticated, have been extinct in North America for thousands of years. Arizona’s free-roaming horses are descendants of domestic horses that returned to a non-domestic state. Their ancestry traces back primarily to Spanish Colonial horses brought by explorers and missionaries in the 17th century, which later interbred with animals lost or abandoned from ranching and mining operations. The distinction between “wild” and “feral” is important because it determines which legal protections and management authorities apply to a specific herd.
Key Habitats and Viewing Locations
The most famous and visible herd is the Salt River horses, found along the Lower Salt River in the Tonto National Forest, northeast of Phoenix. This herd, numbering around 300 horses, frequents the river banks and surrounding recreation areas like Butcher Jones and Saguaro Lake. Their habitat covers approximately 20,000 acres, where they are often seen wading in the river or grazing on river eelgrass.
Other populations fall under federal jurisdiction, primarily managed by the Bureau of Land Management (BLM) in designated Herd Management Areas (HMAs). The Cerbat Mountains HMA, located northwest of Kingman, is one of the few HMAs in Arizona specifically dedicated to horses. Visitors must practice ethical viewing by maintaining a distance of at least 50 feet from the horses and never attempting to feed them, as human interaction can alter their natural behavior and diet.
Legal Status and Management Authority
The legal framework governing Arizona’s free-roaming horses is not uniform and depends entirely on a herd’s location and historical presence. Herds present on federal lands in 1971 are protected by the federal Wild Free-Roaming Horses and Burros Act. The BLM manages these protected herds within specific geographical boundaries called Herd Management Areas (HMAs), aiming to maintain populations at an Appropriate Management Level (AML) to prevent range deterioration.
In Arizona, the BLM manages eight HMAs, setting the AML for all equids (horses and burros) at approximately 1,676 animals across 2.3 million acres. The Salt River herd is a notable exception; because they were not documented on the Tonto National Forest during the 1971 federal survey, they were not granted federal protection. This initially classified them as unauthorized livestock, subjecting them to potential removal.
State legislation, the Arizona Salt River Horse Act (HB2340) signed in 2016, intervened to protect this specific herd. This state law mandated that the Salt River horses are not classified as stray livestock and placed their management under the Arizona Department of Agriculture (AZDA). This created a unique cooperative management structure between the AZDA, the U.S. Forest Service (USFS), and a non-profit advocacy group. This legislative action provides the horses with protection from harassment and removal, distinct from federal protection.
Conservation Efforts and Population Control
Population control is necessary to ensure the health of the horses and the sustainability of their limited habitat. Unchecked populations can quickly exceed the land’s capacity, leading to overgrazing, competition with native wildlife, and poor health for the horses.
The primary method for humane population control used by advocacy groups is the application of Porcine Zona Pellucida (PZP), an immuno-contraceptive vaccine. PZP is administered to female horses via remote darting, a non-invasive process that does not require capture. The vaccine works by triggering an immune response that prevents fertilization for about one year without affecting the mare’s hormonal system or social structure. This method has proven effective, significantly reducing the annual birth rate in the Salt River herd. This humane approach is preferred over traditional roundups and removals, which disrupt herd dynamics and often result in horses being placed in holding facilities. Advocacy groups also play an active role in emergency rescues, monitoring horse health, and providing supplemental feed and water during periods of extreme drought.