Today, the country’s 63 national parks contain at least 247 species of endangered or threatened plants and animals, more than 75,000 archaeological sites, and 18,000 miles of trails.
To determine the most popular national parks in the United States, Stacker compiled data from the National Park Service on the number of recreational visits.
Granite ridges in the park were formed by glaciers that measured up to 9,000 feet thick, and evidence of their presence is visible throughout the park.