The Sampit River begins in a swampy area of western Georgetown County, South Carolina, USA. It flows in an easterly direction to Winyah Bay at Georgetown. Only small crafts can navigate the upper parts of the river. The lower river merges into the bay and is deepened by tidal flows, and (to Georgetown harbor) by dredging.
In 2006, a Pacu was caught in the upper portion of the river. The Pacu is a relative of the Pirana and native to South America. South Carolina DNR officials say this stresses the importance of releasing non-native fish in to the wild. Non-native fish can outcompete the local fish for habitat and food, thus killing them, which could cause huge impacts on fisheries.