Encompassing 2.2 million acres in Wyoming, Montana, and Idaho, Yellowstone has plenty of room for large herds of wildlife, like bison and elk.

Yellowstone National Park

Yellowstone is home to one of the last grizzly bear populations in the country. The Lamar Valley, Hayden Valley, and the Tower-Roosevelt area are top viewing locations.

Spring, summer, and fall are the best times to visit the park to see bears, bison, and elk. Although less likely, you may also be able to spot a gray wolf, wolverine, or lynx.

Katmai in Alaska is one of the best places to view brown bears in the wild, as the park is along the Pacific Coast and offers abundant food sources.

Katmai National Park

Viewing platforms at Brooks Camp on the Brooks River allow visitors to watch bears catch salmon from a safe distance. July is the best time to visit, as the salmon are migrating.

This park in Colorado is home to elk, bighorn sheep, mule deer, moose, 280 bird species, and amphibians, like the endangered boreal toad.

Rocky Mountain National Park

Elk are relatively easy to spot, especially during the fall mating season. To view bighorn sheep, head to Sheep Lakes between May and the middle of August.

As the first national park designated to protect wildlife, 39 mammal species, ranging in size from the diminutive shrew to the imposing moose, call Denali home.

Denali National Park

Grizzlies, Dall sheep, caribou, wolves, foxes, moose, snowshoe hares, and otters are abundant and relatively easy to view sitting high in a bus along Denali Park Road.

Prairie dogs are a much-beloved sight at Sage Creek Campground, Burns Basin Overlook, and Roberts Prairie Dog Town in South Dakota's Badlands National Park.

Badlands National Park

The national mammal of the U.S., the mammoth American Bison, primarily lives in the Badlands Wilderness Area and can best be viewed from the Sage Creek Rim Road.

Bighorn sheep, deer, coyotes, snakes, and large birds of prey are also in the park, and keep your eyes peeled for the butterflies fluttering in the prairie grasses.