Dry Tortugas National Park is a national park in the United States about 68 miles (109 km) west of Key West in the Gulf of Mexico. The park preserves Fort Jefferson and the seven Dry Tortugas islands, the westernmost and most isolated of the Florida Keys. The archipelago’s coral reefs are the least disturbed of the Florida Keys reefs.
The park is noted for abundant sea life, tropical bird breeding grounds, colorful coral reefs, and legends of shipwrecks and sunken treasures. The park’s centerpiece is Fort Jefferson, a massive but unfinished coastal fortress. Fort Jefferson is the largest brick masonry structure in the Western Hemisphere, and is composed of more than 16 million bricks. Among United States forts it is exceeded in size only by Fort Monroe, Virginia, and Fort Adams, Rhode Island. Dry Tortugas is unique in its combination of a largely undisturbed tropical ecosystem with significant historic artifacts. The park is accessible only by seaplane or boat and has averaged about 63,000 visitors annually in the period from 2008 to 2017.Activities include snorkeling, picnicking, birdwatching, camping, scuba diving, saltwater fishing and kayaking.
Dry Tortugas National Park is part of the Everglades & Dry Tortugas Biosphere Reserve, established by UNESCO in 1976 under its Man and the Biosphere Programme.