This year, National Park Services celebrate their 100th birthday. The agency has protected and managed over 59 parks in 27 states and ranges from famed summer-vacation destination like Yellowstone and Yosemite to the remote 8.4 million wild acres of Alaska's Gates of the Arctic and tropical paradises like Florida's Dry Tortugas in the US. Theses parks can be popular destinations for backpackers, who seek head-clearing solitude on the trails. Here are the best 10 best backpacking destination in the US.