SDCL § 31-4-192: State Highway 123 from U.S. Highway 12 to State Highway 15.

The state trunk highway system includes the following in Grant and Roberts counties:

From U.S. Highway 12 southeast of Summit south of the northeast corner of section twenty-five, township one hundred twenty-one north, range fifty west, thence north to State Highway 15 in Wilmont near the northeast corner of section one, township one hundred twenty-two north, range fifty west.