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
In the San Francisco Bay Area, US 101 was originally divided. US 101W followed the same general right-of-way of today's US 101 through the region, primarily along what was originally signed as Bayshore Boulevard. US 101E then generally followed the right-of-way taken by today's I-880 from San Jose to Oakland, then across the Carquinez Bridge to follow what is now SR 37, joining US 101W. The US 101E designation was removed by the 1940s and became SR 17 (later designated as I-880 and the westernmost section I-580), running from San Jose to Oakland and then across the Richmond–San Rafael Bridge. Meanwhile, Bayshore Boulevard was later redesignated as the US 101A bypass and then eventually upgraded to what is now the Bayshore Freeway. The first stretch that was completed between Redwood City and South San Francisco was the Bay Area's first freeway when it opened in 1947. After the entire Bayshore Freeway was completed in the early 1960s, the old alignment along the peninsula was renumbered and renamed as SR 82/El Camino Real.