Which National Park Service park contains Fort Jefferson, the largest brick masonry structure in the Americas?

Dry Tortugas National Park contains Fort Jefferson, the largest brick masonry structure in the Americas.

The massive coastal fortress occupies much of Garden Key in the lower Florida Keys, about 68 miles west of Key West. Its six-sided design includes thick walls, corner bastions, gunrooms, and casemates. Construction used more than 16 million bricks and covered about 16 acres.

Fort Jefferson was built to protect the shipping lanes of the Gulf of Mexico and Caribbean from piracy and hostile naval activity. Construction began in the 1840s, but the fort was never fully completed. During the American Civil War, it also served as a Union military prison; Dr. Samuel Mudd was among its most famous prisoners.

The Dry Tortugas became a national park in 1992. The park protects coral reefs, shallow waters, historic structures, and seven small islands, making Fort Jefferson part of a broader marine and cultural landscape.