Where Are Grizzly Bears in the United States?

Grizzly bears in the lower 48 states occupy a fraction of the territory they once roamed, surviving today in a handful of isolated mountain ecosystems scattered across Montana, Wyoming, Idaho, and the far corners of Washington. Alaska is a different story entirely, with brown bears (the same species) living across most of the state. The contrast between these two realities, one of scarcity and one of relative abundance, shapes nearly every debate about grizzly bear management in the country.

How Much Range Has Been Lost

Before European colonization, grizzly bears ranged across the western half of North America, from the Great Plains through the Rocky Mountains, down into Mexico, and along the Pacific coast from Alaska to California. In the contiguous United States and Mexico, the species has been wiped out from over 99% of that historical range in the last two centuries.¹ The loss was not random. A study tracking where grizzlies persisted between 1850 and 1970 found that bears held on longest in remote Rocky Mountain terrain with whitebark pine forests, and disappeared fastest from areas with growing human populations and where bison and salmon had already been depleted. The authors suggested that the loss of those food sources pushed bears into closer contact with people, accelerating lethal conflict.²

California’s experience captures how quickly things unraveled. The state’s grizzly bear, now immortalized on its flag, vanished through a feedback loop: as human settlement disrupted natural food sources, bears turned to livestock, which fueled persecution campaigns, which drove the bears to extinction by the 1920s.³ That pattern repeated across the West. By the mid-20th century, grizzlies in the lower 48 clung to a few pockets of wilderness in and around the northern Rockies.

The Greater Yellowstone Ecosystem

The Greater Yellowstone Ecosystem, centered on Yellowstone and Grand Teton national parks and spanning parts of Wyoming, Montana, and Idaho, is probably the most famous grizzly bear stronghold in the lower 48. It is also one of the clearest recovery success stories. Between 1990 and 2022, the area occupied by grizzly bears there roughly tripled, expanding from about 9,000 square miles to more than 27,000 square miles.⁴ That expansion has carried bears well beyond the parks, into the surrounding national forests, ranchlands, and even the outskirts of small towns.

This growth has been the subject of fierce legal and political battles. The Yellowstone grizzly population was listed as threatened under the Endangered Species Act in 1975, along with four other lower-48 populations. Federal agencies attempted to delist the Yellowstone population in 2007 by designating it a distinct population segment and removing it from the threatened list, but court challenges restored protections.⁵ The question of whether the Yellowstone grizzly population is recovered enough to manage without ESA protections has gone back and forth for years, with disagreements centering on whether the population’s food base is stable enough and whether it is sufficiently connected to other grizzly populations.

Wolf reintroduction in Yellowstone has also reshaped the landscape for grizzlies in subtle ways. Wolves reduce and redistribute elk herds, which decreases browsing pressure on berry-producing shrubs and other plants that grizzlies depend on. Research has documented what amounts to a trophic cascade: more wolves meant fewer elk in certain areas, which meant more plant-based food for bears.⁶ A broader review concluded that the decades-long absence of wolves, cougars, and grizzly bears from Yellowstone’s northern range was the primary cause of dramatic changes in the ecosystem’s streamside plant communities.⁷

The Northern Continental Divide Ecosystem

Northwest Montana’s Northern Continental Divide Ecosystem, which includes Glacier National Park and the Bob Marshall Wilderness Complex, holds one of the largest grizzly bear populations in the contiguous United States. Population estimates for this area exceed 1,000 animals, making it the biggest concentration of grizzlies in the lower 48.⁸ The landscape here includes a mix of high-elevation wilderness, dense forest, and working ranchland, and bears use all of it. Habitat modeling has shown that a relatively small proportion of the mapped area, roughly 10%, contains the highest-quality habitat and accounts for a disproportionate share of where bears actually spend their time.

The Northern Continental Divide population is significant not just for its size but for its geographic position. It sits closer to the Canadian border and to other smaller grizzly populations than the Yellowstone population does, which makes it a potential source of bears that could help repopulate areas to the west and south.

The Cabinet-Yaak and Selkirk Populations

Not every grizzly bear population in the lower 48 is thriving. The Cabinet-Yaak Ecosystem, which straddles the Montana-Idaho border near the Canadian line, held an estimated 48 to 50 bears as of 2012, roughly half the population recovery goal. Grizzly bear density there was among the lowest of any interior North American population. Worse, the Cabinet and Yaak subpopulations, numbering about 22-24 and 18-22 bears respectively, were essentially cut off from each other. The Cabinet subpopulation was found to be highly inbred.⁹

The Selkirk Mountains, which span the border region of Idaho, Washington, and British Columbia, harbor another small population. Long-term tracking from 1983 to 2002 painted a concerning picture for both areas: 54% of known grizzly bear deaths in the Cabinet-Yaak and 80% in the Selkirks were caused by humans. During that period, the Cabinet-Yaak population was actually declining, while the Selkirk population was growing at a very modest rate.¹⁰ These small, fragile populations represent the thin edge of grizzly bear survival in the lower 48.

Why Connectivity Between Populations Matters

One of the biggest challenges for grizzly bears in the lower 48 is that their remaining populations are separated by highways, developed valleys, and stretches of human-dominated landscape. Research across roughly 100,000 square kilometers in Canada’s southern Rockies, which connect to US populations, found that geographic distance and human footprint both limit genetic connectivity between bear groups.¹¹ In practical terms, male grizzlies do wander between areas often enough to move genes around, but female bears, which disperse shorter distances, rarely cross between subpopulations. That limits the demographic rescue effect: if a small population crashes, females from a neighboring population are unlikely to recolonize it on their own.¹²

Wildlife crossing structures, the overpasses and underpasses built across major highways, offer some help. A study of crossings in Banff National Park found a genetic discontinuity at the Trans-Canada Highway for grizzly bears, meaning the road was acting as a barrier to gene flow. But bears that used the crossings did breed successfully: about 27% of grizzlies documented using the structures were confirmed to have reproduced, and there was evidence of genetic mixing between populations on either side.¹³ That study was done in Canada, but the same principle applies wherever highways bisect grizzly habitat in the US, and it has been influential in arguments for more crossing infrastructure south of the border.

Places Grizzlies Might Return

Two large wilderness areas in the western US are being evaluated as possible future grizzly bear habitat: the North Cascades in Washington State and the Bitterroot Mountains on the Idaho-Montana border.

The North Cascades once supported a substantial grizzly population, but today essentially none remain on the US side. Modeling suggests the ecosystem could support a growing population even under climate change, with high-quality habitat projected to increase through the 2080s. At realistic home-range sizes, the area’s carrying capacity could support roughly 139 female bears under current conditions and potentially 241 to 289 females under future climate scenarios.¹⁴ Simulations suggest that reintroduced bears would concentrate in the mountainous central and northern portions of the ecosystem near the US-Canada border during the early stages.¹⁵

The proposal has divided communities. Research using Q-methodology, which maps how people sort and rank value statements, identified three distinct viewpoints among residents. Two were essentially polarized: one group viewed reintroduction as a moral imperative, while the other saw it as inappropriate and risky.¹⁶ That kind of deep normative divide makes the social side of reintroduction at least as complicated as the biological side.

The Bitterroot Ecosystem in central Idaho presents a different scenario. No active reintroduction program is underway, but grizzly bears from neighboring populations are slowly wandering into the area on their own. Simulations predict that habitat use would concentrate in the northern half of the Bitterroot region under either a natural recolonization or an active reintroduction scenario. Under natural recolonization, bear use would center in Montana initially, then gradually spread more evenly across the northern Bitterroot in Idaho.¹⁷ Earlier modeling estimated the Bitterroot could eventually support somewhere between 321 and 657 bears, depending on the model and season.¹⁸

Alaska’s Brown Bears

Any conversation about where grizzly bears live in the United States has to account for Alaska, which is home to the vast majority of the country’s brown bears. Genetically, coastal Alaska’s large “brown bears” and the smaller interior “grizzly bears” are the same species, with no meaningful genetic barrier between them. The exception is the Kodiak Island population, which appears to have experienced little to no genetic exchange with mainland bears in recent generations.¹⁹

The size difference between coastal and interior Alaskan bears is driven primarily by food, especially salmon. Brown bear densities in coastal areas with abundant salmon runs are 6 to 80 times greater than in interior areas without that food source.²⁰ That staggering range illustrates just how much habitat quality matters. A coastal river system packed with multiple salmon species can support bear densities that interior mountain habitat simply cannot match, and that difference in carrying capacity explains why Alaska harbors tens of thousands of bears while the entire lower 48 supports only about 2,000.

How Climate Change Could Reshape Grizzly Habitat

Climate projections for grizzly bear food resources suggest a mixed picture rather than a uniformly dire one. Modeling in the Greater Yellowstone Ecosystem found that many bear foods are expected to persist or even increase under warmer conditions. But several species are vulnerable, including alpine sweetvetch, a root that grizzlies dig up in spring and fall when little else is available. Some berry species of lower dietary importance also face potential habitat loss.²¹

The broader trend is that bear foods are expected to shift uphill. That creates a particular problem for bears living at lower elevations, which happen to be the ones most likely to encounter people. If food moves upslope and bears at the margins follow it only partway, the animals stuck at lower elevations face both a diminished food base and increased conflict with humans. In the North Cascades, by contrast, modeling suggests climate change would actually improve habitat quality, particularly in the central and western portions of the ecosystem, which is one reason that area scores well for potential reintroduction even decades into the future.

Living Alongside Grizzlies

As grizzly bear range expands in the lower 48, so does the zone of contact with ranchers, hikers, and small-town residents. One emerging practice for reducing conflict with livestock operations is range riding, where riders spend extended periods on horseback monitoring cattle on public grazing allotments. Interviews with people involved in range-riding programs described multiple benefits: fewer livestock losses, better communication between riders and the ranchers or landowners they work with, and a role in sustaining working landscapes as the rural West undergoes economic change.²²

Road management is another dimension of coexistence that gets less public attention. In the Alberta foothills, researchers found that grizzly bears actually selected areas near roads more often than random, with 17 out of 30 bears studied choosing to spend time closer to roads than expected. That does not mean roads are good for bears; it likely means roads are built through the same productive valley-bottom habitats that bears prefer.²³ The overlap between preferred bear habitat and where humans build infrastructure is one of the oldest and most persistent tensions in grizzly bear conservation. Managing road density and seasonal access in grizzly habitat has become a standard tool for reducing lethal encounters, particularly for female bears and cubs that are less willing to cross or navigate busy roads.

If you are hiking, hunting, or working in any of the areas described above, the practical reality is straightforward: carry bear spray, make noise, store food properly, and know the local regulations. The specific areas where encounters are possible are expanding every decade, and the line between “grizzly country” and “not grizzly country” in the northern Rockies is blurrier now than it has been in over a century.