The Apalachicola River is a river, approximately 160 miles (260 km) long, in the state of Florida. The river's large watershed, known as the Apalachicola, Chattahoochee and Flint (ACF) River Basin, drains an area of approximately 19,500 square miles (50,500 km2) into the Gulf of Mexico. The distance to its furthest head waters in northeast Georgia is approximately 500 miles (800 km). Its name comes from Apalachicola Province, an association of Native American towns located on what is now the Chattahoochee River. The Spanish included what is now named the Chattahoochee River as part of one river, calling all of it from its origins in the southern Appalachian foothills down to the Gulf of Mexico the Apalachicola.