S.D. Codified Laws § 49-33-14
There shall be a board of not less than three directors, and such greater number as the bylaws shall designate, to manage the business and affairs of such corporation, who shall be elected at such time, in such manner and for such terms as shall be prescribed by its bylaws and shall hold their office until their respective successors shall be chosen. In the election of directors and at all corporate meetings, each stockholder is entitled to one vote in person or by proxy for each share of stock owned by him. Each stockholder entitled to vote has the right to multiply the number of votes to which such stockholder may be entitled by the number of directors to be elected at the meeting at which the votes are to be cast and cast all of such votes for one candidate, or distribute them among two or more candidates as the stockholder prefers. Vacancies in the board of directors shall be filled in the manner prescribed by the bylaws.
SDCL 49-33-14