The Florida Reef is the only living coral barrier reef in the continental United States. It lies a few miles seaward of the Florida Keys, is about 4 miles wide and extends 270 km (170 mi) from Fowey Rocks just east of Soldier Key to just south of the Marquesas Keys. The barrier reef tract forms a great arc, concentric with the Florida Keys, with the northern end, in Biscayne National Park, oriented north-south and the western end, south of the Marquesas Keys, oriented east-west. The rest of the reef outside Biscayne National Park lies within John Pennekamp Coral Reef State Park and the Florida Keys National Marine Sanctuary. Isolated coral patch reefs occur northward from Biscayne National Park as far north as Stuart, in Martin County. Coral reefs are also found in Dry Tortugas National Park west of the Marquesas Keys. There are more than 6,000 individual reefs in the system. The reefs are 5,000 to 7,000 years old, having developed since sea levels rose following the Wisconsinan glaciation.
Boulder star coral (Montastraea annularis) on Molasses Reef
Elkhorn coral (Acropora palmata) on Molasses Reef
Staghorn coral (Acropora cervicornis) on Looe Key
Long-spined sea urchin (Diadema antillarum)
The Florida Keys are a coral cay archipelago off the southern coast of Florida, forming the southernmost part of the continental United States. They begin at the southeastern coast of the Florida peninsula, about 15 miles (24 km) south of Miami and extend in a gentle arc south-southwest and then westward to Key West, the westernmost of the inhabited islands, and on to the uninhabited Dry Tortugas. The islands lie along the Florida Straits, dividing the Atlantic Ocean to the east from the Gulf of Mexico to the northwest, and defining one edge of Florida Bay. The southern part of Key West is 93 miles (150 km) from Cuba. The Keys are located between about 24.3 and 25.5 degrees North latitude.
Coconut palms in Islamorada, Florida in the Florida Keys
The Keys were formed near the edge of the Florida Platform
Satellite image of the Florida Keys, December 2003
Lower Matecumbe Key to Key Largo, captured by the Sentinel-2 satellite