Washington State Route 20
State Route 20, also known as the North Cascades Highway, is a state highway that traverses the U.S. state of Washington. It is the state's longest highway, traveling across the northern areas of Washington, from U.S. Route 101 at Discovery Bay on the Olympic Peninsula to US 2 near the Idaho state border in Newport. The highway travels across Whidbey Island, North Cascades National Park, the Okanagan Highland, the Kettle River Range, and the Selkirk Mountains. SR 20 connects several major north–south state highways, including Interstate 5 in Burlington, US 97 through the Okanogan–Omak area, SR 21 in Republic, and US 395 from Kettle Falls to Colville.
SR 20's path across the Cascades follows one of the oldest state roads in Washington, established in 1896 as a wagon route. The wagon road fell into disuse within a decade, and the state government postponed the construction of a new route across the North Cascades for several decades. The development of the Skagit River Hydroelectric Project spurred boosters to lobby the state for a new route across Washington Pass, which was opened in 1972. SR 20 originally ran from the Mount Vernon area to Okanogan. By 1973, SR 20 was extended over existing state highways in northern Washington, replacing SR 113 and portions of SR 525 and SR 536 near Port Townsend; SR 30 and SR 294 from Tonasket to Tiger; and part of SR 31 from Tiger to Newport.
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."
Route description
SR 20 begins at a wye junction with US 101 at the southwest end of Discovery Bay on the Olympic Peninsula, just north of the terminus of SR 104. The highway travels northerly through the rural Quimper Peninsula and follows the east shore of Discovery Bay before reaching a junction with SR 19 near Jefferson County International Airport. SR 20 turns north onto the highway and passes Fort Townsend State Park on the southern outskirts of Port Townsend near Glen Cove. Within Port Townsend, the highway travels east through suburban areas as Sims Way and towards the historic downtown as Water Street. To the southwest of Port Townsend's historic district, the route turns southeast into the city ferry terminal. SR 20 continues onto the Port Townsend–Coupeville ferry which travels northeast across the Admiralty Inlet to the Keystone terminal on Whidbey Island. The ferry, operated by Washington State Ferries, takes approximately 30 minutes between terminals and runs year-round.From the Keystone ferry terminal, located adjacent to Fort Casey State Park, the highway travels east between the shore of Admiralty Bay and Crockett Lake, while making a short diversion to the north. SR 20 turns northwest at an intersection with SR 525, which terminates and is supplanted by SR 20. The highway, designated as part of the Cascade Loop and Whidbey Scenic Isle Way state scenic byways, passes the Naval Outlying Landing Field Coupeville and Rhododendron County Park before taking a turn west towards Coupeville and Ebey's Landing National Historical Reserve. SR 20 passes to the south of downtown Coupeville, with eastbound lanes traveling westward and vice versa, and wraps around the western shore of Penn Cove in a long 180-degree turn that passes Fort Ebey State Park. The highway continues northeast into Oak Harbor, where it travels around the downtown area and heads towards Naval Air Station Whidbey Island. SR 20 makes a wide turn around the base's runway and enters Deception Pass State Park. The highway leaves Whidbey Island on the Deception Pass Bridge, crossing over Deception Pass, Pass Island, and Canoe Pass on its way to Fidalgo Island.
SR 20 continues northeast, passing between Lake Campbell and Similk Bay, to Sharpes Corner, where it is joined by a spur route serving Anacortes. SR 20 turns east and supplants the spur route's divided highway, traveling across the Swinomish Reservation and crossing the Swinomish Channel to the Skagit Valley. The highway follows a branch of the BNSF Railway, serving the Shell and Marathon oil refineries on March's Point, along the south side of Padilla Bay. Near Skagit Regional Airport, it intersects SR 536, which connects to Mount Vernon, and veers northeast along a four-lane expressway. SR 20 enters the city of Burlington, where it intersects I-5 and transitions into a city street and turns north onto Burlington Boulevard. The street crosses the BNSF Railway and turns east onto Avon Avenue, crossing the BNSF mainline and joining the North Cascades Highway. SR 20 continues northeast out of Burlington along a branch of the BNSF Railway and the Skagit River into Sedro-Woolley, where it becomes concurrent with SR 9. After bypassing downtown Sedro-Woolley, SR 20 turns east onto Moore Street and exits the city. The highway travels east along the Skagit River, climbing uphill into the Cascade Mountains and passing the towns of Lyman and Concrete, located below Lake Shannon and Baker Lake. At Rockport, SR 20 intersects the eastern terminus of SR 530, which continues towards Darrington and Arlington.
After passing Marblemount, the highway enters North Cascades National Park and Whatcom County. It heads further northeast through Newhalem, a preserved company town for Seattle City Light, and the narrow Diablo Canyon to the Diablo Dam and Diablo Lake, a reservoir that is colored turquoise blue. The roadway makes a long hairpin turn around the southern arm of the lake, crossing it at a narrow point and passing a scenic viewpoint, and continues northeast to Ross Lake. From Ross Lake, SR 20 follows Ruby Creek and Canyon Creek, heading southeast out of the national park and back into Skagit County. The highway crosses Rainy Pass and briefly joins the Pacific Crest Trail as it travels around Whistler Mountain, climbing up into Chelan County. SR 20 turns north and crosses Washington Pass into Okanogan County, making a hairpin turn and beginning its descent into Eastern Washington.
SR 20 travels northeast along Early Winters Creek and the base of Delancy Ridge towards Mazama, where it meets the Methow River. The highway continues southeast along the north side of the river to Winthrop, an old-west-themed town where SR 20 forms the main street between two river crossings. SR 20 heads south through Twisp to a junction with SR 153, where it leaves the Methow River and turns northeast up Frazer Creek towards Loup Loup Pass and the Loup Loup Ski Bowl. The highway descends into the Okanogan Valley near Malott and continues northeast along the Okanogan River to the city of Okanogan. SR 20 takes a turn south over the Okanogan River to join US 97 and bypass the city, while the highway is superseded by SR 215. The concurrent SR 20 and US 97 continue along the east side of the river through the Colville Indian Reservation, intersecting SR 155 in eastern Omak and SR 215 to the north of another river crossing. The highway travels north through the farming community of Riverside to Tonasket, where SR 20 leaves US 97 and takes a turn east towards the Okanogan Highlands.
It climbs Bonaparte Creek and crosses Wauconda Pass, near Mount Bonaparte and the ghost town of Wauconda, before beginning its descent into Republic. SR 20 enters Republic on 6th Street and turns south onto Clark Avenue, the town's main street, before coming to a junction with SR 21. The highway turns northeast onto the Sherman Pass Scenic Byway, carrying the concurrent SR 20 and SR 21, and follows the Sanpoil River. SR 21 leaves the byway at Sanpoil Lake, while SR 20 travels into the Kettle River Range along O'Brien Creek. The highway dips south into the Colville National Forest and climbs the ridge, crossing Sherman Pass in a series of hairpin turns. The pass, located above sea level, is the highest in the state. SR 20 descends along Sherman Creek towards Franklin D. Roosevelt Lake on the Columbia River, which it crosses on a highway concurrent with US 395. The two routes travel east through Kettle Falls, intersecting SR 25, and follow the Colville River upstream to the city of Colville.
At Colville, SR 20 turns east away from US 395 and continues into the southern reaches of the Selkirk Mountains. The highway forms the northern boundary of the Little Pend Oreille National Wildlife Refuge and follows the Little Pend Oreille River north through a series of glacial lakes. After entering Pend Oreille County, SR 20 makes a series of hairpin turns to descend into the Pend Oreille Valley. At an intersection with SR 31 in Tiger, the highway turns south to follow the Pend Oreille River, becoming part of the International Selkirk Loop and Pend Oreille Scenic Byway in the process. SR 20 continues south along the river, joined by the Pend Oreille Valley Railroad, and intersects SR 211 at Usk. Approximately southeast of Usk, the highway terminates at US 2, just west of the Washington–Idaho state line.
Names and designations
Portions of SR 20 are known as the North Cascades Highway, which is a designated Washington State Scenic Byway and a National Forest Scenic Byway. The Sherman Pass Scenic Byway begins at Republic, and extends east across the mountainous Kettle River Range, Colville National Forest, and the Columbia River through Kettle Falls to Sherman Pass.The highway also forms most of the Washington segment of U.S. Bicycle Route 10, which travels between Anacortes and the Montana state border.
Annual closure
SR 20 is one of only five State Routes in Washington that have portions closed in the winter. Washington Pass and nearby Rainy Pass annually receive up to of snow throughout the winter, and are prone to avalanches leaving over of snow on the road., the median first open date was April 21. The median final closure date was November 24. During the drought of the winter of 1976/77, the highway was not closed.