Isle Royale National Park is in Michigan.
The park occupies Isle Royale and more than 400 smaller islands in northwestern Lake Superior. Although the island lies closer to Ontario and is near Minnesota, it is part of the U.S. state of Michigan, specifically Keweenaw County. That geography makes the question easy to confuse: the park is remote from Michigan’s mainland but still legally within Michigan.
Isle Royale became a national park on April 3, 1940. Its isolation has made it a remarkable natural laboratory, especially for the long-running study of wolves and moose. Researchers have followed the predator-prey relationship there since 1958, examining how changing moose numbers, wolf numbers, food supply, disease, climate, and genetic isolation interact.
The park is not in Wisconsin, New York, or Minnesota. Minnesota is the nearest mainland state in some directions, while Ontario is across the lake, but neither contains the national park. Access is primarily by ferry, seaplane, or private boat, and the park is known for its wilderness character.