Hayden Valley is one of Yellowstone's classic wildlife-watching areas, a broad open stretch along the Yellowstone River where bison, elk, coyotes, bald eagles, and water birds are often seen. Grizzly bears are possible in spring and early summer, especially around newborn bison and elk.
Pull-outs along the road make it easy to stop with binoculars or a spotting scope. Early morning and evening are usually best, and traffic can slow sharply when animals are close to the road.