The highways of this state consist of streets and alleys within the limits of municipal corporations, the state trunk highway system, the county highway systems of the several counties, and all other highways denominated secondary highways. Source: SDC 1939, § 28.0107.
Classification of highways of state
SDCL § 31-1-4 — under DEFINITIONS AND CLASSES OF HIGHWAYS.
SDCL § 31-1-4