Ellicott Rock is important historically because it marks the boundary between three states
(Oconee County). Ellicott Rock is located in the Ellicott Rock Wilderness Area that overlaps parts of South Carolina, Georgia, and North Carolina. Located in extreme northwestern South Carolina in Sumter National Forest, the wilderness area contains 2,859 acres in South Carolina. Ellicott Rock is found within the Blue Ridge terrain, which is made up of rock that formed from Precambrian sediments and volcanics that were later metamorphosed into the hard schists and gneisses of the area. The Blue Ridge was emplaced during the formation of South Carolina in the Ordovician period and then was thrust up and over younger rocks to its present location. The Blue Ridge rocks in South Carolina are found only in Oconee County. Ellicott Rock is a metamorphic gneiss that is characteristic of the Blue Ridge region.
Ellicott Rock is important historically because it marks the boundary between three states. Andrew Ellicott, a surveyor, was commissioned by North Carolina and Georgia to determine the South Carolina/Georgia boundary, which he accomplished in 1811. At the completion of his survey, he cut a mark into the rock on the east bank of the Chattooga River. The rock and the wilderness area are named after his accomplishment. Later his findings were challenged by other surveyors, who altered the boundary in 1813 when they recalculated it and moved the thirty-fifth parallel to ten feet south of Ellicott Rock. They inscribed another rock, which is also visible today, with the inscription “LAT 35A 1813 NC+SC.”
Frazier, Joey. “In Quest of . . . Ellicott’s Infamous Rock.” Sandlapper 6 (summer 1995): 14–15.
Murphy, Carolyn H. Carolina Rocks! The Geology of South Carolina. Orangeburg, S.C.: Sandlapper, 1995.