Lee County, one of the last frontiers settled in southwest Florida, lies between the Everglades and the Gulf of Mexico and contains a variety of interconnected ecosystems preserved for visitors, students, and researchers. Its natural and historic sites include JN "Ding" Darling National Wildlife Refuge on Sanibel Island, a 6,400-acre refuge with abundant bird, reptile, amphibian, and mammal life; Cayo Costal Island State Park, a large undeveloped barrier island with beaches, dunes, nesting loggerhead sea turtles, and bird habitat; Lovers Key Carl E. Johnson State Park, a 1,463 acre park of four barrier islands with beaches and recreation; Koreshan State Historic Site, a restored religious community settlement on the Estero River dating to the early 1900s; Mound House Archaeological and Historic Site, a nearly three acre Calusa shell mound with the oldest house on Fort Myers Beach and evidence of 2,000 years of island life; Randell Research Center at Pineland Archeological Site, a 200-acre Calusa site occupied for more than 1,500 years with shell mounds and middens overlooking Pine Island Sound; C.R.E.W., a 60,000-acre watershed spanning Lee and Collier counties with trails through pine flatwoods, marsh, oak hammocks, and popash communities; 4 Mile Cove Ecological Preserve, a 365-acre saltwater wetland preserve with mangrove forest and brackish marsh; Bonita Beach; Matanzas Pass Preserve, a 56-acre maritime hammock retreat; Lynn Hall Memorial Park; Bowditch Point, a 17-acre beach park on the bay and Gulf; Lakes Regional Park, a 279-acre park with 158 acres of freshwater lakes; Six Mile Cypress Slough Preserve, a 2,500-acre wetland ecosystem; Manatee Park, Lee County's winter home for the manatee; Hickey's Creek Mitigation Park, an 862-acre wildlife preserve; and Caloosahatchee Regional Park, a 768-acre park for outdoor recreation.