But the predators were aggressively hunted and sometimes killed for bounties through the early 20th century. By the mid-20th century, the only places gray wolves could be found below the Canadian border were a sliver of land in northern Minnesota and Michigan's Isle Royale.

The species was then protected under the Endangered Species Act in the 1970s. Conservation efforts and reintroduction programs helped gray wolves return to parts of their range. There are now more than 5,000 gray wolves in the continental United States, primarily in the western Great Lakes states of Michigan, Minnesota and Wisconsin, and the northern Rocky Mountain states of Idaho, Montana and Wyoming, as well as eastern Oregon and Washington.