Seneca River (South Carolina)

The Seneca River is created by the confluence of the Keowee River and Twelvemile Creek in northwestern South Carolina, downriver from Lake Keowee near Clemson. It is now entirely inundated by Lake Hartwell, forming a 21-mile-long (34 km) arm of the lake. The Seneca River and the Tugaloo River join to form the Savannah River.

Map of Seneca River, South Carolina, USA

The boundary between the Seneca River and the Keowee River has changed over time. In the Revolutionary War period, the upper part of the Seneca River was often called the Keowee River.

In current times, the section of the Keowee River between the Keowee Dam and its confluence with Twelvemile Creek is called the Seneca River on many maps, including the official county highway map. Since this area is flooded by Lake Hartwell formed by damming the Seneca and Tugaloo rivers, it is natural to refer this section as the Seneca instead of its proper name.