S.D. Const. art. XXVI, § 13

First assembly of Legislature--Oaths of office. The Legislature elected under the provisions of this ordinance and Constitution shall assemble at the temporary seat of government on the third Tuesday in October, in the year A. D. 1889, at 12 o'clock noon, and on the first day of their assemblage the Governor and other state officers shall take the oath of office in the presence of the Legislature. The oath of office shall be administered to the members of the Legislature and to the state officers by the chief justice of the territory, or by any other officer duly authorized by the laws of the territory of Dakota to administer oaths.