The ruins were found last fall on the banks of the May River in the southern coastal town of Bluffton. A letter written in 1796 by a visitor mentions the octagonal house and helps date the structure.
Archaeologists Heather Cline and Mary Socci say the 900-square-foot house was owned by Scottish immigrant William McKimmy and was built about 1790.
That would mean the home predates Thomas Jefferson’s Poplar Forest. That home was built in the 1820s near Lynchburg, Va., and is considered to be the first octagonal house in the U.S.