SDCL § 31-4-143: State Highway 19 from Nebraska to State Highway 34.

The state trunk highway system includes the following in Clay, Turner, Minnehaha, and Lake counties:

(1) From a point on the Nebraska state line south of Vermillion, thence northerly via Vermillion to State Highway 46 south of Centerville;

(2) From a point on State Highway 46 east of Irene, thence north via Viborg, Parker, and Humboldt to State Highway 34 southeast of Madison.