Grand Canyon National Park
Annual visitors: 5.5 million
Location: Arizona
Size: 1,902 square miles
Founded: 1919
Highlights: One of the most famous parks in the system, its namesake ravine is 277 river miles long, up to 18 miles wide and a mile deep. The park service offers free shuttles to the South Rim, which includes Grand Canyon Village, Scenic Hermit Road and Desert View Drive.
