You are now at the top of the ramp facing east. You are standing on the parapet looking over the rampart and the curtain wall to the mouth of the Saint Marys River. This is the reason this fort is here. This opening to the Atlantic provides access to the deep south with deepwater ports in Fernandina Beach, Florida, and Saint Marys, Georgia. The Saint Marys River leads to the Okefenokee Swamp and gives Florida its puzzle-piece-shaped border in its northeast corner. Its location was critical to control waters from Savannah to St Augustine. The addition of rail in north Florida from the island allowed for the transfer of goods across Florida to Tampa instead of the long trip around the state.