In 1904, twelve years before the National Park Service Organic Act was signed and the National Parks Service was officially created, American park rangers began documenting the number of visitors to the national parks. Then, 120,000 people came through the gates of the 11 nationally designated lands.
In just over a century, that number has skyrocketed. In 2015, more than 307 million people visited the service's 410 sites, which include 59 parks as well as historic sites, parkways, lakeshores, memorials, and recreation areas. It was a record-breaking year for national parks, and attendance was up 4.9 percent over the previous year's total.
But where do visitors tend to flock? Read on for the most-visited national parks. Who knows, you may even feel inspired to head on a outdoorsy vacation to celebrate the National Park Service's 100th anniversary!