St. Marys is a city in Camden County, Georgia, United States, located on the southern border of Camden County on the St. Marys River in the state's Low Country. The Florida border is just to the south across the river, Cumberland Island National Seashore is to the northeast, and Kingsland, Georgia, is to the west. Jacksonville, Florida, is 38 miles south, and Savannah, Georgia, is 110 miles north. The city is home to the National Seashore's visitor center and boat access; the St. Marys Submarine Museum, and Crooked River State Park.