The American Bison (Bison bison) is an icon of North America, and its presence in Arizona represents a significant conservation success story. Once nearly eliminated, these massive herbivores now inhabit specific regions of the state, primarily in the northern highlands. Monitoring these populations is a continuous process involving multiple agencies working to balance herd health with ecological impacts. Understanding the number of bison in Arizona requires looking at the distinct groups and the specific management goals that shape their numbers.
Current Bison Population Figures
The total number of American Bison in Arizona’s managed herds fluctuates due to ongoing conservation and reduction efforts, but the total population is generally in the hundreds. As of 2024, the largest and most dynamic group is the Kaibab Plateau herd, which had a summer population estimate of approximately 378 animals. This herd, which freely moves between the Kaibab National Forest and Grand Canyon National Park, is the primary factor influencing the state’s total count.
Separate from the Kaibab Plateau herd is the managed population within the House Rock Wildlife Area (HRWA), which has an established population objective between 80 and 200 bison. The state also maintains the smaller Raymond Ranch herd near Flagstaff, which is managed for specific genetic characteristics and currently numbers less than 50 individuals. Combining the approximate figures from these distinct groups suggests the total wild and managed bison population in Arizona ranges roughly from 500 to 650 animals.
Distinct Arizona Herds and Their Management
Arizona’s bison population is divided into at least three distinct groups, each with its own management structure and numerical targets. The largest, the Kaibab Plateau herd, is managed collaboratively by the National Park Service (NPS) and the Arizona Game and Fish Department (AZGFD), given its range across Grand Canyon National Park and adjacent national forest lands. The NPS has a long-term goal of reducing the herd size to fewer than 200 animals to mitigate the negative impacts of overgrazing on sensitive park resources like vegetation, water sources, and archaeological sites.
To achieve this reduction goal, the NPS utilizes methods such as live capture and transfer, where bison are relocated to American Indian tribes through the Intertribal Buffalo Council. The AZGFD also manages regulated public hunts outside the park boundaries, which helps control the number of animals that wander onto national forest land.
Separately, the AZGFD manages a conservation herd concentrated within the 54,000-acre House Rock Wildlife Area (HRWA) on the Kaibab National Forest, with an objective to keep the population within the 80 to 200 range. A third, much smaller herd exists at Raymond Ranch, managed primarily to conserve a genetically distinct lineage of bison.
The History of Bison Reintroduction in Arizona
The presence of American Bison in Arizona traces back to a reintroduction effort in the early 20th century, following the species’ near-extinction across North America. Bison had been extirpated from the region by the mid-1600s. The foundational stock for the Kaibab Plateau herd was brought to the state in 1906 by frontiersman Charles Jesse “Buffalo” Jones.
Jones initially imported approximately 125 bison to the Kaibab Plateau with the distinct goal of crossing them with domestic cattle to create a hardy hybrid animal, sometimes called a “cattalo”. The hybridization effort was largely unsuccessful for commercial purposes but established a new population of bison in the area. The initial herd eventually settled in the House Rock Valley, and the State of Arizona officially acquired management of the herd in 1926.
The Arizona Game and Fish Department managed this population within the House Rock Wildlife Area for decades, maintaining a stable herd of around 100 animals. In the 1990s, factors like drought, fire, and hunting pressure on the edges of their range encouraged a portion of the herd to seek refuge and better forage on the adjacent, protected lands of the Grand Canyon National Park’s North Rim. This migration established the large, free-ranging Kaibab Plateau herd that is the focus of current management efforts.