US Highway 101

El Camino Real


US 101 is perhaps the most historic highway in California. It follows the route the Spanish explorer Juan Gaspar de Portola followed in 1769, which later became El Camino Real, the King's Highway. This historic road connected the 21 missions of California and served as the main north/south road in California until the 1920s. North of San Francisco it is known as the "Redwood Highway," which is considered by many to be the most scenic road in California. At one time its route followed the famous Avenue of the Giants, which goes by the tallest trees in the world located in the Redwood State and National Parks. Even though this road was surpassed by US 99 and later I-5, it remains an important road linking cities along the coast of California.

US 101 at a Glance

Original Routing

US 101 was commissioned in 1926 as one of the original US highways. It originally went from the Mexican Border south of San Diego to Olympia, Washington. Between the Mexican Border and Los Angeles it followed the route of I-5, and in fact, many parts of I-5 were originally built as US 101. Its new southern terminus is the East LA Interchange where it intersects with I-5, I-10, and SR-60. From that point north it followed what is essentially its current routing. For two-thirds of its length in California, it followed El Camino Real to the last mission in the chain, Mission San Francisco Solano in Sonoma. However, to the north of San Francisco it is known as the Redwood Highway. In Oregon and Washington it followed just about exactly the same route it does now, following the coast from the Oregon-California border north to the Olympic Peninsula in Washington, curving to the east, then to the south, finally ending in Olympia, Washington, ending at US 99; now I-5.

Current Status Outside of California

It appears there are only few changes to US 101 outside of California. The only apparent differences are upgrades to the road and the fact that it now ends at I-5 in Olympia, WA instead of US 99. The section along the Oregon coast is spectacular, especially as most of the famous bridges on it have been or are being preserved.

Current Status in California

South of Los Angeles, US 101 was completely changed. Originally, from 1926 through the 1940s - 1950s, US 101 went nowhere near its final alignment with I-5 from Los Angeles to southern Orange County. The 1926 route faithfully followed old El Camino Real from San Diego to Sonoma. From Los Angeles to the Mexican Border, However, many sections were upgraded to freeways, which altered its course to then it was decommissioned and replaced by I-5.

US 101 has largely remained unchanged to the north of Los Angeles. With a few exceptions, it follows its original path, set down in 1926. Between Los Angeles and the Bay Area and , the only change to US 101 has been the upgrade from two/three lane road to four lane limited access highway, from the 1940s onward. Even these upgrades have had little effect as many entailed adding an extra two lane carriageway. In 1992, a landmark on this stretch of US 101 was finally eliminated: the last traffic signals at Santa Barbara were finally removed. It is now possible to go from Los Angeles to San Francisco to  along along US 101 without ever encountering a traffic signal. However, while US 101 is at least four lanes the whole distance between Los Angeles and San Francisco, this does not mean it is now up to Interstate standards,. Much of this highway is still very windy and almost half is still at expressway status, with at-grade cross streets.

In the Bay Area, US 101 was transferred from El Camino Real (now SR-82) to the Bayshore Fwy (former BYP 101) in 1964 as a part of California's major highway system renumbering. Many sections to the north of San Francisco are being converted from two lane conventional highway to four lane freeway/expressway. In cities such as Eureka and Crescent City or even San Francisco, US 101 is still the main street passing the the middle of the city, complete with signals. Though an inconvenience in this era of freeways, these sections offer an interesting glance of how other US highways went through cities prior to being bypassed by Interstates.


Intersections and Routings with other US Routes in California

Variations of US 101

US 101 Guides

South: Mexican Border to Ventura (Under Construction):

Central: Ventura to San Francisco (Future):

North: Golden Gate to Oregon Border (Future).

US 101 Photo Albums

The US 101 "Photo Album" will eventually have more pictures than for other US Highways on this site. It is divided into several sections, all of which will be fine tuned.

Mexican Border to downtown San Diego.

San Diego:  Features Pacific Highway and alignments dating between 1930 and 1958.
Page 1: Pre-1940
Page 2: 1940-1958

Oceanside - Carlsbad Freeway: Built in 1952-53, this freeway exists as part of I-5 and also separately as part of Carlsbad Blvd.
Page 1: Carlsbad
Page 2: Oceanside

North San Diego and South Orange Counties

San Clemente: This page features photographs of the I-5 freeway which was completed in 1960 and was the last major section of US 101 to be signed on a new alignment south of Los Angeles.

South Orange County: Covers the original alignments of US 101 through the construction of the San Diego Freeway in 1959.

Simi Valley: 1930 alignment and 1953 expressway.

Other US 101 Pages

San Diego Highways: US 101 Andy Field

101 Cafe ( This page features the historic cafe located in Oceanside as well as a plethora of great post card scans and interesting regional history.


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