S.D. Codified Laws § 31-3-36

Public highways may be located without the appointment of viewers, provided the written consent of all the owners of the land to be used for that purpose be first filed in the county auditor's office, and if it is shown to the satisfaction of the board of county commissioners that the proposed highway is of sufficient public importance to be opened and worked by the public, it shall make an order locating the same, from which time only shall it be regarded as a public highway.