South Dakota Codified Laws 7-1-64. Union County boundaries
Beginning at a point where the township line between townships ninety–five and ninety–six north intersects the boundary line between the states of South Dakota and Iowa, thence west and along the township line between townships ninety–five and ninety–six north, to the northwest corner of township ninety–five, range fifty, west of the fifth principal meridian; thence south and along the range line between ranges fifty and fifty–one west, to the boundary line between the states of South Dakota and Nebraska; thence southeasterly and along said last mentioned state line to its intersection with the boundary line between the states of South Dakota and Iowa; thence northerly and along the boundary between the states of South Dakota and Iowa, to the place of beginning.
Source: SL 1863-4, ch 14, § 1; SL 1870-1, ch 10, § 1; SD SenJRes 4, 1905; Act of Congress approved March 1, 1905, ch 1295, 33 Stat. 820; SL 1907, ch 245, § 1; SDC 1939, § 12.0165.