Apalachicola Bay is an estuary and lagoon located on Florida's northwest coast renowned for its oysters. The Apalachicola Bay system also includes St. Georges Sound, St. Vincent Sound and East Bay, covering an area of about . Four islands St. Vincent Island to the west, Cape St. George Island and St. George Island to the south, and Dog Island to the east separate the system from the Gulf of Mexico. Water exchange occurs through Indian Pass, West Pass, East Pass and the Duer Channel. The lagoon has been designated as a National Estuarine Research Reserve and the Apalachicola River is the largest source of freshwater to the estuary. Combined with the Chattahoochee River, Flint River, and Ochlockonee River they drain a watershed of over at a rate of per second according to the United States G