National Parks Traveler
Though few people seem to know or care, Michigan's long-ago abolished Mackinac National Park was America's second national park. Yellowstone got there first, but not by much.
On March 1, 1872 President Ulysses S. Grant signed a law establishing that Yellowstone would forever be "dedicated and set apart as a public park or pleasuring ground for the benefit and enjoyment of the people." Yellowstone thus became the first true national park in America and the world. What few people seem to know is that Congress created a second national park just three years later. Michigan's Mackinac National Park, which existed from 1875 to 1895, is the "forgotten" national park.
https://www.nationalparkstraveler.org/2011/05/pruning-parks-mackinac-national-park-1875-18958079