U.S. Route 101
The nearly highway's northern terminus is in Tumwater, Washington: the route remains along the Olympic Peninsula's coastal perimeter west, north, and east; the northernmost point on the highway is in Port Angeles. The southern terminus of US 101 is in Los Angeles at the East Los Angeles Interchange, the world's busiest freeway interchange.
U.S. Route 101 in Washington
US 101 enters Washington from Oregon on the Astoria–Megler Bridge, a bridge that carries vehicles across the Columbia River near its mouth; it is the longest continuous truss bridge in North America and among the longest of its kind in the world. At the north end of the bridge is an intersection with State Route 401 (SR 401), where US 101 turns west to follow the north bank of the river, forming part of the Lewis and Clark Trail Scenic Byway. The highway passes under Fort Columbia State Park in a tunnel and continues along the Willapa Hills through Chinook towards Baker Bay. At the head of the bay, near Port of Ilwaco Airport, US 101 intersects a short alternate route that bypasses the coastal section of the highway. US 101 then dives southwesterly along the Wallacut River into Ilwaco, where it runs through town as Spruce Street before turning north onto 1st Avenue after an intersection with SR 100.