SDCL § 12-19-42: Envelope containing voted ballots kept closed--Delivery to county board.

Upon receipt of the sealed return envelope containing the voted ballots, the person in charge of the election shall keep it in a safe place without opening the envelope or breaking the seal thereof. The person in charge of the election shall cause to be delivered to the absentee ballot counting board, the absentee ballot, or ballots with the election supplies, or if later received, then prior to the close of the polls.