S.D. Codified Laws § 11-2-14
For any of the purposes specified in § 11-2-13, the board may divide the county into districts of such number, shape, and area as may be deemed best suited to carry out the purposes of this chapter; and within the districts it may regulate and restrict the erection, construction, reconstruction, alteration, repair, or use of buildings, structures, or land . All such regulations shall be uniform for each class or kind of buildings throughout each district, but the regulations in one district may differ from those in other districts.
The regulations shall be made in accordance with a comprehensive plan and designed to lessen congestion in the streets; to secure safety from fire, panic, and other dangers; to promote health and the general welfare; to provide adequate light and air; to prevent the overcrowding of land; to avoid undue concentration or scattering of population; to facilitate the adequate provision of transportation, water, sewerage, schools, parks; and other public requirements.
The regulations shall be made with reasonable consideration, among other things, to the character of the district, and its peculiar suitability for particular uses, and with a view to conserving the value of buildings and encouraging the most appropriate use of land throughout the county.
SDCL 11-2-14