S.D. Codified Laws § 11-2-41
The application for establishment or enlargement of a special zoning area shall be a petition verified by one or more applicants, by affidavit stating that the affiant personally witnessed the signatures on the petition and believe the signatures to be genuine, and shall be subscribed by not less than one-third of the whole number of qualified voters residing within the proposed special zoning area. The petition shall be filed with the county auditor and presented to the board for consideration at its next meeting. If the board chooses to propose the establishment or enlargement of a special zoning area on its own initiative, the board may by resolution propose the establishment or enlargement of the special zoning area at any regular meeting of the board. After the board has adopted a resolution proposing the establishment or enlargement of a special zoning area, the board shall publish notice and hold a public hearing on the question as provided in §§ 11-2-43 and 11-2-47.
SDCL 11-2-41