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 California
US 101 crosses into the Mendocino County line as a freeway for one mile (1.6 km), but then narrows to an expressway through the Russian River canyon and eventually a two-lane road south of Hopland, the first time since leaving San Francisco. Just before reaching Ukiah, US 101 becomes a four-lane freeway. In the community of Calpella, SR 20 merges with US 101 for the next to Willits. The freeway portion ends as the combined US 101 and SR 20 ascend the Ridgewood Summit, the highest elevation along the route's trek through California. As 101 resumes freeway status just south of Willits, SR 20 splits from 101 shortly before 101 suddenly reverts to a 2-lane undivided freeway and eventually a highway north of Willits.