U.S. 101 in California

U.S. Route 101
Map of California with US 101 highlighted in red
Route information
Defined by
Maintained by Caltrans
Length:	808.111 mi (1,300.529 km) Portions of US 101 have been relinquished to or are otherwise maintained by local or other governments, and are not included in the length.
Existed:	November 11, 1926 (1926-11-11) – present
Major junctions
South end:	I-5 / I-10 / SR 60 in Los Angeles
	SR 110 in Los Angeles I-405 in Sherman Oaks I-280 / I-680 in San Jose I-880 in San Jose I-280 in San Francisco I-80 in San Francisco I-580 in San Rafael SR 1 in Leggett SR 299 in Arcata US 199 near Crescent City
North end:	US 101 at Oregon state line
Location
Counties:	Los Angeles, Ventura, Santa Barbara, San Luis Obispo, Monterey, San Benito, Santa Clara, San Mateo, San Francisco, Marin, Sonoma, Mendocino, Humboldt, Del Norte
Highway system
United States Numbered Highway System List Special Divided Replaced State highways in California Interstate U.S. State Pre-1964 History Unconstructed Deleted Freeway Scenic ← SR 99 SR 103 →

U.S. Route 101 (US 101) in the state of California is one of the last remaining and longest U.S. Routes still active in the state, and the longest highway of any kind in California. US 101 was also one of the original national routes established in 1926. Significant portions of US 101 between the Los Angeles area and the San Francisco Bay Area follow El Camino Real, the historic road connecting the former Alta California's 21 missions.

Although the highway has been superseded in overall importance for transportation through the state by Interstate 5 (I-5), US 101 continues to be the major coastal north–south route that links the Greater Los Angeles Area, the Central Coast, the San Francisco Bay Area, and the North Coast (Redwood Empire). Generally referred to as "101" by residents of Northern California, in Southern California it often called "The 101" (pronounced "the one oh one"). The highway has portions designated as the Santa Ana Freeway, the Hollywood Freeway, the Ventura Freeway, South Valley Freeway, and Bayshore Freeway. The Redwood Highway, the 350-mile-long (560 km) northernmost segment of the highway, begins at the Golden Gate and passes through the world's tallest and only extensive preserves of virgin, old-growth coast redwood trees.