Cumberland Island, Georgia's largest and southernmost barrier island. Here pristine maritime forests, undeveloped beaches and wide marshes whisper the stories of both man and nature. Cumberland Island is also home to over 9,886 acres of Congressionally designated Wilderness. Cumberland Island is approximately 18 miles long and between one-half and 3 miles wide ÃƒÆ’Ã¢â‚¬Å¡Ãƒâ€šÃ‚Âor about 40 square miles. Cumberland Island National Seashore preserves most of Cumberland Island in Camden County, Georgia, the largest of Georgia's Golden Isles. The seashore features beaches and dunes, marshes, and freshwater lakes. The national seashore also preserves and interprets many historic sites and structures.