Fort Jefferson is a massive but unfinished coastal fortress. It is the largest brick masonry structure in the Americas, and is composed of over 16 million bricks. Among United States forts, only Fort Monroe in Virginia and Fort Adams in Rhode Island are larger. The fort is located on Garden Key in the lower Florida Keys within the Dry Tortugas National Park, about 70 miles west of the island of Key West.
Since 2003, Freedom Cement has supplied its Century Brand Natural Cement to National Park Service masonry contractor Stone & Lime Imports, Inc. to support ongoing restoration of the fort's crumbling brick walls.