SDCL § 31-1-1: Highway defined.

Every way or place of whatever nature open to the public, as a matter of right, for purposes of vehicular travel, is a highway. The term, highway, does not include a roadway or driveway upon grounds owned by private persons, colleges, universities, or other institutions, but the term includes a roadway or driveway upon grounds owned by any state agency, college, university, or institution if the governing agency, board, or commission by resolution so determines and the Department of Transportation concurs.