 The interior consists of a maritime forest (the density of which has been reduced by development) and freshwater sloughs.The Savannah River empties into the Atlantic Ocean just north of Tybee Island, placing the island in a historically strategic location.To the west, the marsh-lined Lazaretto Creek splits the island off from McQueens Island (the stretch between the main western shore of Tybee Island and Lazaretto Creek is mostly marshland).