S.D. Codified Laws § 31-18-3
The board of county commissioners may vacate or change the location of any section-line highway under its jurisdiction and the board of supervisors of an organized township may vacate or change the location of any section-line highway under its jurisdiction, as provided in this title, but neither board may vacate or change any portion of the state trunk highway system or any highway constructed by state or federal aid or any highway within the limits of a municipal corporation. A board of supervisors may not vacate or change any portion of the county highway system, nor may a board of county commissioners vacate or change any portion of the township road system. No board of county commissioners or board of supervisors may vacate a section-line highway that provides access to public lands or public waters embracing an area of not less than forty acres. This section does not prohibit the closing of a section-line highway to vehicular traffic if the highway is unsafe for vehicular traffic.
SDCL 31-18-3