Dry Tortugas

Group of seven small islands in Monroe County, southwestern Florida. Located at the entrance to the Gulf of Mexico, 108 km/67 mi west of Key West, the Dry Tortugas are known for their marine wildlife and migratory birds. The largest of the islands is Loggerhead Key, which is less than 1.6 km/1 mi long.

The Dry Tortugas were discovered in 1513 by the early French explorer Henri Ponce de León (1513), who named them after the many tortoises he saw there. They were once a hotbed of piracy, and many shipwrecks occurred on their shoals. Fort Jefferson, the largest all-masonry fort in the Western hemisphere, was built in 1846–66 on Garden Key and was used as a Union prison during the Civil War. Since 1935 the Dry Tortugas have constituted the Fort Jefferson National Monument.