SDCL § 8-3-12: Supervisor elected at annual meeting--Representation of county seat town.

There shall be elected at such annual township meeting one supervisor, who shall hold his office for the term of three years and until his successor is elected and qualified, the senior member of the board of supervisors to be chairman thereof. In any organized civil township containing an unincorporated platted town which is a county seat, at least one member of such board shall be a resident voter of such town.