St. Marys is a city in Camden County, Georgia, set on the St. Marys River at the state's southeastern corner, directly across the water from Florida. With a population of about 18,300, it anchors the Kingsland, Georgia Micropolitan Statistical Area and serves as the coastal heart of a county shaped by maritime industry, the military, and tourism. The city traces its origins to a Spanish mission settlement in the mid-16th century and was formally established in 1787, making it one of the oldest continuously inhabited communities in the United States. The city's identity is inseparable from the water. Its downtown historic district, listed on the National Register of Historic Places, holds Victorian and antebellum homes, churches, and a waterfront that was once a shipbuilding and trading hub. Today that waterfront is the embarkation point for the passenger ferry to Cumberland Island National Seashore, a protected barrier island about seven miles offshore that draws visitors for its wild beaches, maritime forest, and ruins of the Carnegie-era Dungeness estate. Naval Submarine Base Kings Bay, located adjacent to St. Marys on the East River, is the U.S. Atlantic Fleet's home port for Ohio-class submarines and one of the region's largest employers. Its presence brings a steady military and civilian population to the area and shapes the local economy alongside tourism, shrimping, and retail. Jacksonville, Florida, about 38 miles south, extends a larger metropolitan job market within commuting distance. Residential St. Marys spans the walkable historic grid near the river, established in-town neighborhoods, and newer subdivisions and planned communities farther out, including gated waterfront developments such as Cumberland Harbour. Interstate 95 passes six miles west, linking the city to Brunswick and Savannah to the north and Jacksonville and its airport to the south. For many, St. Marys offers the rare combination of deep history, a working waterfront, military community energy, and direct access to an undeveloped national seashore.