Apalachee Bay is a bay in the northeastern Gulf of Mexico occupying an indentation of the Florida coast to the west of where the Florida peninsula joins the United States mainland. It is bordered by Taylor, Jefferson, Wakulla, and Franklin counties. The Aucilla, Econfina, St. Marks, and Ochlockonee rivers drain into the bay. It is named for the Apalachee tribe which lived between the Aucilla and Ochlockonee rivers until the 18th century. Most of the bay's coast is the St. Marks National Wildlife Refuge.