SDCL § 34-10-4: Joint action of county commissioners of two or more counties.

If the district extends into two or more counties, the boards of county commissioners shall, within thirty days after the filing of such petition, meet in joint session and canvass the same, and if found to be signed by the requisite number of resident electors in the district, they shall by joint action order such election and appoint judges and clerks of election as provided in § 34-10-3. Such joint session and all subsequent joint sessions required by this chapter shall be held at the county seat of the county having the largest portion of its territory included within the boundaries of said proposed district.