S.D. Codified Laws § 7-1-27
Current with legislation signed by the governor on or before 3/6/2024
Beginning at the point where the township line between townships one hundred and one hundred one north intersects the center of the main channel of the Missouri River, thence west and along said township line to its intersection with the tenth guide meridian west, being the northwest corner of township one hundred north of range seventy-three west of the fifth principal meridian; thence south and along said guide meridian to the boundary line between the states of South Dakota and Nebraska; thence east and along said state line to the center of the main channel of the Missouri River; thence northwesterly and up the center of the main channel of said Missouri River to the place of beginning.
SDCL 7-1-27