Savannah (river, United States)
Savannah, river, 314 mi (505 km) long, formed by the confluence of the Tugaloo and Seneca rivers and flowing SE to the Atlantic Ocean; with the Tugaloo it forms the entire S.C.–Ga. boundary. Savannah, Ga., the largest port on the river, is the head of navigation for oceangoing ships. Clark Hill Dam (completed 1954) and Hartwell Dam (1961) above Augusta, Ga., are part of the Savannah River basin development plan; the U.S. Department of Energy's Savannah River Site, which manufactures nuclear weapons, is also on the river.