The state trunk highway system includes the following in Butte, Lawrence, Meade, Ziebach, Haakon, Stanley, Hughes, Hyde, Buffalo, Jerauld, Sanborn, Miner, Lake, and Moody counties:

1. (1) From a point on the Wyoming state line southeasterly to Interstate Highway 90;
2. (2) From a point on Interstate Highway 90 easterly via Sturgis to U.S. Highway 14;
3. (3) From a point on U.S. Highway 14 in Pierre, thence easterly via Pierre, Wessington Springs, Lane, Woonsocket, Artesian, Roswell, Vilas and Howard to U.S. Highway 81; and
4. (4) From a point on U.S. Highway 81 at Madison easterly via Madison, Colman, and Egan to the Minnesota state line.

Source: SL 1984, ch 209 , § 29; SL 2005, ch 150 , § 2; SL 2026, ch 125 , § 1.