Located on Mackinac Island. The park encompasses 2.81sq mi, which is approximately 74% of the island's total area of 3.78 sq mi and is within the boundaries of the city of Mackinac Island and has permanent residents within its boundaries. M-185 circles the perimeter of the park as the only motorless highway in the state due to the island's ban of automobiles. On July 15, 2009, the park celebrated its 20 millionth visitor.
The park was first established as Mackinac National Park in 1875, which was the second national park established in the United States after Yellowstone National Park. In 1895, it was transferred to state control and reorganized as Mackinac Island State Park, which was the first state park in Michigan. The park contains many important historical and geological features, such as Fort Mackinac, Fort Holmes, other historic buildings, historic sites, limestone caves, and other unique rock formations. The park also operates the Mackinac Island Airport.