1. Great Smoky Mountains National Park Location: North Carolina, Tennessee Size: 521,896 acres Established: June 15, 1934 2015 attendance: 10.7 million Other facts: The park has 384 miles of mountain roads. On a typical weekend summer day, tens of thousands of people can be found driving through the park. The Smoky Mountains are among the oldest on Earth. The park is home to more than 100 native species of trees. The park is a United Nations World Heritage Site.