Isle Royale

Isle Royale is the least-visited national park in the contiguous United States, not because it isn't worth visiting, but because reaching it takes real commitment: a ferry ride of one and a half to six hours across Lake Superior, the largest freshwater lake on Earth, or a seaplane flight from the mainland. There are no roads and no cars anywhere on the island; everything beyond the dock happens on foot, by canoe, or by private boat.

The island is also famous among ecologists for a decades-long predator-prey study of its moose and wolf populations, isolated enough from the mainland that their numbers rise and fall in a rare, closely watched natural cycle. Isle Royale is the only national park that closes entirely each winter, from November 1 through mid-April, both for visitor safety and to give researchers exclusive access to the frozen island.

Come for the isolation. Stay for the fact that very few people ever make the trip, so most of what you find, you'll find largely alone. Read the story, book your ferry well ahead, and when you leave, collect the stamp.