The state trunk highway system includes the following in Aurora County:
From a point on Interstate Highway 90 south of Plankinton in the southeast corner of section twenty-two, township one hundred three north, range sixty-four west, thence east via Plankinton to U.S. Highway 281 south of the northeast corner of section twenty-four, township one hundred three north, range sixty-four west.
SDCL 31-4-224