John Pennekamp Coral Reef State Park is a Florida State Park located on Key Largo in Florida, and includes approximately 70 nautical square miles (240 km²) of adjacent Atlantic Ocean waters. It was the first underwater park in the United States. The park was added to the National Register of Historic Places on April 14, 1972. The primary attractions of the park are the coral reefs (such as Molasses Reef) and their associated marine life.