South Dakota Codified Laws 7-1-68. Ziebach County boundaries
Beginning at the northeast corner of township seventeen north of range twenty–one, east of the Black Hills meridian, thence west and along the township line between townships seventeen and eighteen north, to the one hundred second meridian of west longitude; thence south and along said meridian to the center of the main channel of the Cheyenne River; thence easterly and along the center of the main channel of said Cheyenne River to its intersection with the sixth guide meridian, east, being the range line between ranges twenty–four and twenty–five, east Black Hills meridian; thence north and along said guide meridian to its intersection with the forty–fifth parallel of north latitude; thence west and along said parallel to its intersection with the range line between ranges twenty–one and twenty–two, east; thence north and along said range line to the place of beginning.
Source: SL 1911, ch 107, § 1; SDC 1939, § 12.0170.