S.C. Code Ann. § 4-3-130

Chesterfield County is bounded as follows: on the north by the North Carolina line; on the east by Marlboro County from which it is separated by Great Pee Dee River; on the south by Darlington County from which it is divided by Cedar Creek, commencing at its mouth where it enters into the Great Pee Dee, and up said creek to the head of the southernmost branch, and thence by a direct line S. 51° 45' W., to the fork of Lynch's River; on the southwest by Kershaw and Lancaster Counties from which it is separated by Lynch's River.