The Styx River is a 41.3-mile-long (66.5 km) river in the state of Alabama. It rises in Baldwin County near the town of Bay Minette in the southwestern part of the state and is a tributary to the Perdido River. It is named for the River Styx in Greek mythology. Where U.S. Highway 90 crosses the river by bridge, the attendant sign reads "Charon Retired".