How Many Bison Are Left in North America? Herds Today

Bison numbers today at a glance

Bison numbers come from different counts made in different years, so totals are approximate. Figures compiled by the National Bison Association from government and park sources give this picture for the early 2020s:

Commercial herds vs conservation herds

For conservation, the key question is not how many bison exist but how they live. Commercial herds are raised mainly for meat. Animals are often selected for traits such as calm temperament and fast growth, sold or slaughtered young, and kept in fenced pastures. They help keep bison on the land, but they do not behave or evolve like wild herds.

Conservation herds are managed mainly for the species itself, with natural sex and age structures, some exposure to natural selection and, in the best cases, predators such as wolves. A major IUCN review in 2010 counted about 20,500 plains bison in 62 conservation herds, plus several thousand wood bison in a smaller number of northern herds. The IUCN estimates that only around 15,000 bison can be called wild and free-ranging, not mainly confined by fences. Many conservation herds are small, with a few hundred animals or fewer, which makes it hard to keep their genetic diversity in the long run.

How many bison are in Yellowstone?

Yellowstone National Park holds the most important wild herd of plains bison. It is the only place in the lower 48 states where bison have survived in the wild continuously since prehistoric times, descended from about two dozen animals left in 1902 and a small number brought in from private herds.

In recent years, the park’s population has ranged from about 3,500 to nearly 6,000. The 2025 estimate, made before calves were born in spring, was nearly 5,300. The park has two main breeding groups: the northern herd around the Lamar Valley and the central herd that breeds in the Hayden Valley. Numbers swing with harsh winters and with management: when large numbers migrate out of the park into Montana in winter, some are captured and moved to tribal lands or culled, partly because of concerns about brucellosis spreading to cattle. More about seeing them is in our guide to the animals of Yellowstone.

Wood bison and Canada’s herds

The larger wood bison of the north has its own recovery story. Thought to be nearly lost after plains bison were moved into Wood Buffalo National Park in the 1920s and crossbred with the local animals, a relatively pure herd of about 200 was found in a remote part of the park in 1957. Animals from it founded herds at Elk Island National Park in Alberta and in the Mackenzie Bison Sanctuary in the Northwest Territories.

Wood Buffalo National Park, on the border of Alberta and the Northwest Territories, still holds the largest free-roaming herd of wood bison, a few thousand animals, although many of them carry bovine tuberculosis and brucellosis. Other wood bison herds live in Yukon, British Columbia and northern Alberta. In 2015, wood bison were released in the Innoko River area of western Alaska, the first wild wood bison in the US for more than a century.

Tribal and other public herds

Some of the fastest growth in conservation herds is on tribal lands. The InterTribal Buffalo Council, founded in 1990, supports dozens of member tribes in restoring bison, and tribal herds in the US and Canada together hold roughly 30,000 animals. Since the 2010s, Yellowstone bison that pass quarantine for brucellosis have been moved to the Fort Peck Reservation in Montana and from there to other tribes.

Other important public herds include Wind Cave and Theodore Roosevelt national parks, Custer State Park in South Dakota (around 1,300–1,500 bison), the Henry Mountains in Utah, the Wichita Mountains Wildlife Refuge in Oklahoma, Grasslands and Prince Albert national parks in Saskatchewan, and Banff National Park in Alberta. In Mexico, small herds have been restored in northern Chihuahua and Coahuila.

Genetic purity and other concerns

Almost all plains bison today descend from fewer than 100 animals that survived the 1880s, so genetic diversity is lower than it once was. In addition, several of the ranchers who saved bison crossbred them with cattle. Modern DNA tests have found small amounts of cattle genes in most herds, including many public ones.

Herds that show no evidence of cattle genes, such as Yellowstone and Wind Cave, are therefore especially valuable as sources for new herds. Since 2020, the US Department of the Interior has moved bison between its herds to keep genetic diversity high. Disease, limited space and conflicts with cattle grazing remain the main obstacles to larger, free-roaming herds.

Has the bison recovered?

In numbers, the recovery of the American bison is a remarkable success: from about 1,100 animals in 1889 to around 400,000 today. As a wild species, it is only partly recovered. The IUCN lists the bison as Near Threatened because wild herds are few, small and isolated, and they occupy only a tiny fraction of the former range. To understand how the species came so close to disappearing, read why did bison almost go extinct?