SDCL § 31-12A-36: Annexation of area--Procedures.

A contiguous area may be annexed to a road district by circulation of an initiating petition for annexation signed by twenty-five percent of the eligible voters in the area to be annexed and twenty-five percent of the eligible voters in the existing district, similar to an initiating petition specified in this chapter.

Upon receipt of an initiating petition and passage of a resolution by the directors finding that the petition is valid, the area shall be annexed if a majority of the eligible voters in the area to be annexed and a majority of the eligible voters in the existing area vote in favor of the annexation in the same manner as prescribed for creation of a new road district.