The state trunk highway system includes the following in Charles Mix, Bon Homme, Yankton, Clay, and Union counties:

From a point on U.S. Highway 18 in the southeast quarter of section four, township ninety–five north, range sixty–five west, thence east via Wagner, Irene, and Beresford to the Iowa state line near the northeast corner of section fifteen, township ninety–five north, range forty–eight west.

Source: SL 1984, ch 209, § 39.