S.D. Codified Laws § 15-3-10
Whenever it shall appear that the occupant, or those under whom he claims, entered into the possession of premises under claim of title, exclusive of any other right, founding such claim upon a written instrument as being a conveyance of the premises in question, or upon the decree or judgment of a competent court, and that there has been a continued occupation and possession of the premises included in such instrument, decree, or judgment, or of some part of such premises under such claim for twenty years, the premises so included shall be deemed to have been held adversely; except that where the premises so included consist of a tract divided into lots the possession of one lot shall not be deemed a possession of any other lot of the same tract.
SDCL 15-3-10