The Ashley River is a blackwater / tidal river in South Carolina, rising from the Wassamassaw and Great Cypress Swamps in Western Berkeley County. It consolidates its main channel about 5 miles west of Summerville, widening into a brackish, tidal estuary just south of Fort Dorchester. The much wider Ashley joins the Cooper River in Charleston to form the Charleston Harbor before discharging into the Atlantic Ocean, or, as South Carolinians like to say, 'the Ashley River joins the Cooper River to form the Atlantic Ocean.'