The Combahee River is a short blackwater river in the southern Lowcountry region of South Carolina formed at the confluence of the Salkehatchie and Little Salkehatchie rivers near the Islandton community of Colleton County, South Carolina. Part of its lower drainage basin combines with the Ashepoo River and the Edisto River to form the ACE Basin. The Combahee empties into Saint Helena Sound near Beaufort, which in turn empties into the Atlantic Ocean.