Great White Heron National Wildlife Refuge protects a vast stretch of the lower Florida Keys Backcountry on the Gulf side of the island chain, from north of Marathon to north of Key West. Established on October 27, 1938, it serves as a haven for great white herons, migratory birds, and other wildlife. Covering 130,187 acres, it is overwhelmingly water, with marine and coastal waters far exceeding its land area, and about 1,900 acres set aside as wilderness. Its mangrove islands, pine rockland, tropical hardwood hammock, and shallow waters support species including the Miami blue and nesting or feeding sea turtles.