While Yellowstone continues to be good beaver habitat, it's not as robust as the Adirondacks. Through the decades the population has varied greatly. In recent years, the park's beaver population probably has hovered around 1,000 spread out across roughly 140 colonies.

In 2026, the beaver population in Yellowstone National Park is considered a major success story of ecological restoration, with numbers estimated to be around 100 to 150 individuals across various colonies. Historically, beavers were nearly wiped out of the park due to trapping and the degradation of their habitat. Their return is closely linked to the famous reintroduction of wolves in the mid-1990s. The presence of wolves changed the behavior of elk, preventing them from overgrazing on willow and aspen trees along the riverbanks. This allowed the vegetation to recover, providing the essential food and building materials beavers need to thrive. Today, beaver colonies can be found in several areas of the park, including the Lamar Valley and the Willow Park area. As "ecosystem engineers," their dam-building activities help create wetlands that provide habitat for fish, birds, and other mammals, while also helping to filter water and mitigate the effects of drought. While 100-150 might seem like a small number for such a large park, it represents a stable and functioning population that continues to expand into new territories.