Isunigu (also called Seneca, Esseneca, and Sinica) was a Cherokee town on the Keowee River.
It was on the west side of the Keowee River, near the mouth of Coneross Creek, in today's Oconee County, South Carolina.
In the late 18th and early 19th centuries, the Cherokee ceded their land of the Lower Towns to South Carolina.
The site of Isunigu, a settlement that likely had more than a thousand years of previous indigenous habitation, as did other towns in the area, was flooded by the creation in the 20th century of Lake Hartwell.
The meaning of the name Isunigu is lost, along with the artifacts and other materials from prehistoric and historic years now submerged under Lake Hartwell.