Ellenton was a town that was on the border between Barnwell and Aiken counties, South Carolina, United States. Settled circa 1870. In 1950 the town was acquired by the U.S. Atomic Energy Commission as part of a site for development of the Savannah River Plant, a nuclear plant. All the residences and businesses were acquired, and two new towns, New Ellenton, South Carolina and Jackson, South Carolina, were built. The plant was between the current CSX railroad and the current SC Highway 125, Upper Three Runs Creek, and Four Mile Branch. SC Highway 125 was U.S. Highway 278 in the 1950s.