High Quality Content by WIKIPEDIA articles! State Route 9 (SR 9) is a 98.17-mile (157.99 km) long state highway traversing three counties, Snohomish, Skagit and Whatcom, in the U.S. state of Washington. The highway extends north from an interchange with SR 522 in the vicinity of Woodinville north through Snohomish, Lake Stevens, Arlington, Sedro-Woolley and Nooksack to become British Columbia Highway 11 (BC 11) at the Canadian border in Sumas. Three other roadways are briefly concurrent with the route: SR 530 in Arlington, SR 20 in Sedro-Woolley and SR 542 near Deming. A spur route in Sumas serves trucks traveling into British Columbia.