S.D. Codified Laws § 5-3-10
No person shall acquire any vested rights in and to any islands or land described in § 5-3-9, by reason of residence thereon or improvement thereof, except as herein provided. Any person who, for five years next prior to the first day of July 1911, shall have resided upon and improved any such land, shall have the right to purchase not to exceed one hundred sixty acres of the same, at the price in cash at which it is appraised by the commissioner of school and public lands, and the commissioner shall, upon petition filed in his office, within a reasonable time thereafter, appraise such land and sell and convey the same to such petitioner at the appraised price, upon satisfactory proof of the residence and improvement required by this section, payment thereof to be made within sixty days after notice to the petitioner of such appraisement.
SDCL 5-3-10