Which national park is hardest to visit?

Its hard to say which national park is the most difficult to visit. There are numerous locations across multiple geographies including Guam, American Samoa, Northern Mariana Islands, Puerto Rico, The U.S Virgin Islands and the United States itself. Many national parks don't receive a lot of visitors because of their remote locations. Alaska contains many national parks that are hard to visit including: Kobuk Valley National Park, Katmai National Park and Preserve, And Gates of the Arctic. Gates of the Arctic National Park for example is the least visited overall park because its extremely remote and can only be reached by plane or on foot. Other National Parks like Isle Royale in Michigan or Dry Tortugas National Park in Florida are also hard to visit as they can only be reached by boat or seaplane and contain rugged terrain and sensitive reefs.