Washington State Route 538
The highway, which has existed as a county road since 1911, travels from Interstate 5 (I-5) in the west, passing former U.S. Route 99 (US 99), now Riverside Drive, and Skagit Valley College's main Mount Vernon campus before terminating at a roundabout with SR 9.Before being designated Secondary State Highway 1G (SSH 1G) in 1937, the current roadway that is now SR 538 was a county road through farmland for 26 years.State Route 538 (SR 538) begins at the Interstate 5 (I-5) interchange in northern Mount Vernon located south of the Skagit River.[14] Between early June and late July 2007,[15][16] the Washington State Department of Transportation (WSDOT) constructed a roundabout at the SR 9 and Schopf Lane intersection,[17][18] the first in Skagit County.[19][20] A city-led project to widen the section of College Way that passes under I-5 at the western terminus of SR 538 began construction in December 2018 and was completed in 2020.