S.C. Code Ann. § 27-2-30: Plane coordinates for expressing position of point defined.

The plane coordinates of a point on the earth's surface, to be used in expressing the position or location of a point in the State, consist of two distances, expressed in feet and decimals of a foot. One of these distances, to be known as the easting (x-coordinate), gives the distance in an east-and-west direction; the other, to be known as the northing (y-coordinate), gives the distance in a north-and-south direction. These coordinates must be made to depend upon and conform to the coordinates, on the South Carolina Coordinate System, of the monumented points of the North American Horizontal Geodetic Control Network as published by the United States Coast and Geodetic Survey (now the National Geodetic Survey) within this State as those coordinates have been determined by the survey.