The Blackwater River of Florida is a 56.6-mile-long (91.1 km) river rising in southern Alabama and flowing through the Florida Panhandle to the Gulf of Mexico. The river enters Florida in Okaloosa County and flows through Santa Rosa County to Blackwater Bay, an arm of Pensacola Bay. The river passes through Blackwater River State Forest and Blackwater River State Park. Milton, the county seat of Santa Rosa County, is located on the river.The Blackwater's sandy bottom, white beaches and large sandbars contrast with the dark tannic water that gives the river its name. "Blackwater" is a translation of the Choctaw word oka-lusa, which means "water black".