Ellenton was a town that was located on the border between Barnwell County and Aiken County, South Carolina, United States. Settled around 1870, it was the site in September 1876 of a violent attack against blacks over several days by white militia, resulting in the death of at least 35 blacks and likely as many as 100, part of efforts to intimidate blacks by violence prior to the fall elections to suppress their voting.
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 a new town, New Ellenton, was built. The plant was located 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.
The settlement began with the construction of the Port Royal and Augusta Railroad, which was later renamed the Charleston and Western Carolina Railway. It was taken over by CSX Transportation. It ran through the plantation of Robert Jefferson Dunbar. Part of his land was for the railroad right-of-way, the train station, and town.
Oral tradition of the town tells that Stephen Caldwell Millet, the superintendent of the railroad construction and president of the railroad, boarded with the Dunbar family. He was so struck with the beauty of Ellen Dunbar, the nine-year-old daughter of the Dunbars, that he asked his company to name the station "Ellen's Town." In a note to the O'Berry book, the Savannah River Archeological Research Program indicates that in 1870, when this was supposed to have taken place, Mary Ellen Dunbar was twenty-two years old.
Aiken County was established in 1871 during the Reconstruction era. In 1875 its population of adult white males was 2494 and that of adult black males was about 1,000 more. In their drive to take back political and social power in the state, white Democrats used intimidation and outright violence in the following years to discourage freedmen from voting. During the election of 1876 at the end of Reconstruction, several armed conflicts took place in Aiken County and nearby areas of South Carolina prior to the election. The Piedmont, with counties split narrowly between the races, broke out into violence, as had happened at previous elections. White paramilitary groups, related to the thousands of men in rifle clubs, formed chapters of Red Shirts and worked to disrupt black Republican organizing, voting and other political activities.