SDCL § 15-5-10: Trial of action in county where commenced unless defendant demands change of venue.

If the county designated for that purpose in the complaint is not the proper county, the action may, notwithstanding, be tried therein unless the defendant, before the time for answering expires, demands in writing that the trial be had in the proper county, and the place of trial be thereupon changed by the consent of the parties or by order of the court, as provided in § 15-5-11.