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."