10. Isle Royale National Park – Michigan
This isolated island park on Lake Superior is only accessible by boat or seaplane, making it one of the most remote in the U.S. Though it’s less visited, the park’s rugged terrain and limited resources make it dangerous for the unprepared.
There are stories of hikers vanishing during solo treks, never seen again. Once the ferry leaves, you’re completely cut off from the mainland—and from help.