State Road No. 15 Cascade Highway was added to the state highway system in 1931. This route began at Jct. State Road No. 1 Pacific Highway (US 99) in Everett and headed easterly via Snohomish, Monroe, Skykomish, Stevens Pass, and Leavenworth, ending at Jct. State Road No. 2 Sunset Highway (US 10/US 97) between Peshastin and Leavenworth. At first the Cascade Highway used the unpaved roadway across Stevens Pass built jointly by King and Chelan Counties in cooperation with the National Forest Service. After the state took over the route the state realigned and paved the highway in stages during the 1930s and 40s. In 1937, this highway was redesignated as Primary State Highway 15. State Road No. 15 had no branches.
Primary State Hwys Secondary State Hwys
State Roads 1923-37