S.D. Codified Laws § 26-9-14
No sentence shall be suspended or final judgment or execution stayed, in the case of any person found guilty under § 26-9-1, to exceed a period of two years. If at any time prior thereto it shall appear to the satisfaction of the court that such person has complied faithfully with the conditions of any suspended sentence, judgment, or execution, or is for any cause in the opinion of the court entitled to be released therefrom, the court may suspend such sentence indefinitely, in which case such person shall be finally released and discharged, as he shall be in any event at the end of two years from imposition of any such sentence. But if any defendant be actually serving a jail sentence imposed under § 26-9-1 and enforced before the expiration of such two years in accordance with the provisions of this chapter, then in such case the defendant shall not be finally discharged until the expiration of any such sentence.
SDCL 26-9-14