Other seacoast fortifications in the National Park System are: Castle Clinton National Monument, in New York Harbor; Fort McHenry National Monument and Historic Shrine, at Baltimore, Md.; Fort Sumter National Monument, in Charleston Harbor, S. C.; Fort Frederica National Monument, Ga.; Castillo de San Marcos and Fort Matanzas National Monuments, at St. Augustine, Fla.; Fort Jefferson National Monument, in the Dry Tortugas Islands, about 68 miles from Key West, Fla.; and San Juan National Historic Site, San Juan, Puerto Rico.