Dry Tortugas National Park is a national park located 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. 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.