The Dry Tortugas are a small group of islands. They are at the end of the Florida Keys, United States. They are about 113 kilometers (70 mi) west of Key West, and 60 km (37 mi) west of the Marquesas Keys, at , the closest islands. Still farther west is the Tortugas Bank, which is now underwater. The islands were discovered in 1513 by Spanish explorer Juan Ponce de León. They are an unincorporated area of Monroe County, Florida and belong to the Lower Keys Census County Division. With their surrounding waters they make up the Dry Tortugas National Park.