S.D. Codified Laws § 31-4-152 (2026)
The state trunk highway system includes the following in Union, Lincoln, Minnehaha, Moody, Brookings, Deuel, Hamlin, Codington, Grant, and Roberts counties: From a point on the Iowa state line near the center of section twenty-six, township eighty-nine north, range forty-eight west, thence northerly via North Sioux City, Sioux Falls, Brookings, and Watertown to the North Dakota state line on the north line of section thirty, township one hundred twenty-nine north, range forty-nine west.
Source: SL 1984, ch 209 , § 25.