SDCL § 31-4-138: U.S. Highway 16 from Wyoming to Interstate Highway 190.

The state trunk highway system includes the following in Custer and Pennington counties:

From a point on the Wyoming state line on the west line of section thirty, township three south, range one east, thence easterly and northeasterly via Custer and Hill City to the intersection of 8th Street and Omaha Street in Rapid City, thence westerly to Interstate Highway 190 at the intersection of West Boulevard and Omaha Street.