SDCL § 31-4-170: State Highway 50 from State Highway 34 to Iowa.

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

(1) From a point on State Highway 34 east of Fort Thompson, thence southerly via Chamberlain to Interstate Highway 90 south of Chamberlain;

(2) From a point on Interstate Highway 90 south of Pukwana, thence southerly and easterly to State Highway 44 west of Platte;

(3) From a point on State Highway 44 east of Platte, thence southerly and easterly to U.S. Highway 18 in Lake Andes;

(4) From a point on U.S. Highway 18 east of Lake Andes, thence south to State Highway 46 west of Wagner;

(5) From a point on State Highway 46 east of Wagner, thence southerly and easterly via Avon, Tyndall, and Tabor to U.S. Highway 81 north of Yankton;

(6) From a point on U.S. Highway 81 at the intersection of Broadway Street and 4th Street in the city of Yankton, thence easterly via Yankton and Vermillion to the Iowa state line.