The basics: The park occupies more than half of the island of St. John and includes adjacent underwater worlds. It offers not only sandy beaches and snorkeling among coral reefs, but also mangroves, lush mountains and valleys, hiking trails and the ruins of early islanders. Of seven species of sea turtles in the world, three inhabit the waters of St. John; the most common are green and hawksbill turtles.
Visitors: 438,372 people visited the park in 2015.
Square miles: 23, including land and water.
Founded: 1956.
More information: nps.gov/viis; 1-340-776-6201.
