SDCL § 7-8-6: Redistricting and transition after increase in number of commissioners.

If at such election a majority of all votes cast is for an increase, the board within one hundred eighty days after the votes have been canvassed shall redistrict the county into numbered districts. As to any members of such board whose terms of office extend for an additional two years beyond the next general election, the tenure of office is not affected, and in redistricting the county the board shall designate the districts to be represented by such members. The commissioner shall be a resident of the district that the commissioner is designated to represent. Each district for which representation is not provided by such designations shall, at the next ensuing general election, elect a commissioner, the term of office to be determined as provided in § 7-8-1.