State Route 20 (
SR 20), also known alternately as the
North-Cross Highway or the
North Cascades Highway, is a state route in the state of
Washington. It travels from an intersection with
U.S. Route 101 (US 101) at
Discovery Bay near
Port Townsend to
Newport at a junction with
US 2 about from the
Idaho state line. Although
US 12 has a larger east–west extent, SR 20 is the longest highway in Washington at , only longer than US 12. The highway has been called "The Most Beautiful Mountain Highway in the State of Washington."