 Prior to the 1964 highway renumbering, SR 502 was part of Secondary State Highway 1S (SSH 1S), which was established in 1937.The highway traveled south from its current western terminus until the construction of a new interchange with I-5 in 2008, part of a project to widen SR 502 and install a median barrier on the roadway.SR 502 begins as the four-lane Battle Ground Highway at exit 11 on I-5, a trumpet interchange located north of Mount Vista, and travels due east as 219th Street, crossing Gee Creek and passing the northbound Gee Creek rest area.