SDCL § 9-3-1: Minimum population of municipalities.

A municipality may not be incorporated unless it contains at least one hundred legal residents and at least forty-five registered voters. For the purposes of this section, a person is a legal resident in the proposed municipality if the person actually lives in the proposed municipality for at least ninety days of the three hundred sixty-five days immediately preceding the filing of the petition or is an active duty member of the armed forces whose home of record is within the proposed municipality.