ISLE ROYALE NATIONAL PARK, MICHIGAN
This gorgeous park near Thunder Bay, Canada, is the largest island in the world’s largest freshwater body, Lake Superior. Though it ranks as the fifth least-visited park in the nation, it has the highest backcountry use. It’s accessible only by boat or seaplane, and is one of the few national parks to close in winter. The isolation makes this a unique bio-preserve. Isle Royale has freshwater clams, snails, and insects in sizes and densities not seen elsewhere since the 1800s. It’s also the only place where moose and wolves can coexist without bears to balance the predator pole. While you’re there, check out the boat tour around the park’s satellite islands: there are about 400 of them.