Gray's Reef National Marine Sanctuary , designated in January 1981, is one of the largest near shore live-bottom reefs in the southeastern United States. The sanctuary is located 17.5 nautical miles off Sapelo Island, GA, and one of 14 marine protected areas that make up the National Marine Sanctuary System that encompass more than 150,000 square miles of marine and Great Lakes waters from Washington State to the Florida Keys, and from Lake Huroon to American Samoa; and one of three marine sanctuaries that make up the Southeast Region.
Within the 17-square-nautical-mile sanctuary, there are both rocky ledges and sandy flat places. The reefs' rock ledges, submerged beneath 60 to 70 feet of water, can be as tall as 6-8 feet and are highly complex-they have nooks and crannies and bumps and plenty of places for invertebrates to latch on to and for fish to hide. Together these animals form a dense carpet of living creatures that in places completely hides the rock. That gives the habitat of Gray's Reef its common name-a "live bottom".