The Waccamaw River is a river, approximately 140 miles (225 km) long, in southeastern North Carolina and eastern South Carolina in the United States. It drains an area of approximately 1,110 square miles (2886 km2) in the coastal plain along the eastern border between the two states into the Atlantic Ocean. Along its upper course, it is a slow-moving, blackwater river surrounded by vast wetlands, passable only by shallow-draft watercraft such as canoe. Along its lower course, it is lined by sandy banks and old plantation houses, providing an important navigation channel with a unique geography, flowing roughly parallel to the coast.

Lake Waccamaw is a fresh water lake located in Columbus County in North Carolina. It is the largest of the natural Carolina Bay lakes. Although bay trees are present within many Carolina Bays, the term "bay" does not refer to the trees but comes instead from an early science publication by Glenn (1895), who used the word "bay" to refer to these features near the town of Darlington, South Carolina. Lake Waccamaw is fed by four creeks: First, Second, Third, and Big creeks. The outlet forms the Waccamaw River which flows south-southwest to empty into the Atlantic Ocean near Georgetown, South Carolina