This is a list of

Interstate Highways The Dwight D. Eisenhower National System of Interstate and Defense Highways, commonly known as the Interstate Highway System, or the Eisenhower Interstate System, is a network of controlled-access highways that forms part of the National H ...

in the

U.S. state In the United States, a state is a constituent political entity, of which there are 50. Bound together in a political union, each state holds governmental jurisdiction over a separate and defined geographic territory where it shares its so ...

California California () is a U.S. state, state in the Western United States that lies on the West Coast of the United States, Pacific Coast. It borders Oregon to the north, Nevada and Arizona to the east, and shares Mexico–United States border, an ...

that have existed since the 1964 renumbering. It includes routes defined by the

California State Legislature The California State Legislature is the bicameral state legislature of the U.S. state of California, consisting of the California State Assembly (lower house with 80 members) and the California State Senate (upper house with 40 members). ...

but never built, as well as routes entirely relinquished to local governments. Each state highway in California is maintained by the

California Department of Transportation The California Department of Transportation (Caltrans) is an Executive (government), executive department of the U.S. state of California. The department is part of the Government of California#State agencies, cabinet-level California State Tran ...

(Caltrans) and is assigned a ''Route'' (officially ''State Highway Route'') number in the Streets and Highways Code (Sections 300-635). Under the code, the state assigns a unique ''Route X'' to each highway and does not differentiate between state, US, or Interstate highways.

Overview

Lengths for each state route were initially measured as they were during the 1964 state highway renumbering (or during the year the route was established, if after 1964) based alignment that existed at the time, and do not necessarily reflect the current mileage. Portions of some routes have been relinquished to or are otherwise maintained by local or other governments, and may not be included in the length listed below. Several routes are broken into non-contiguous pieces, and their lengths may not reflect the overlaps that would be required to make them continuous. Some routes may also have a gap because it is either explicitly defined in the California Streets and Highways Code or due to an unconstructed portion, and the listed length may or may not reflect the gap. Additionally, if a route was renumbered, the old or new number is given in the "notes" column. Years shown are when legislative action was taken, not when real-world changes were made. Concurrencies are not explicitly codified in the Streets and Highways Code; such highway segments are listed on only one of the corresponding legislative route numbers—for example, the

I-80 Interstate 80 (I-80) is an east–west transcontinental freeway that crosses the United States from San Francisco, California, to Teaneck, New Jersey, in the New York metropolitan area. The highway was designated in 1956 as one of the ori ...

/ I-580 concurrency, known as the

Eastshore Freeway Interstate 80 (I-80) is a transcontinental Interstate Highway in the United States, stretching from San Francisco, California, to Teaneck, New Jersey. The segment of I-80 in California runs east from San Francisco across the San Francisc ...

, is only listed under Route 80 in the highway code while the definition of Route 580 is broken into non-contiguous segments. When a highway is broken into such segments, the total length recorded by Caltrans only reflects those non-contiguous segments, and does not include those overlaps that would be required to make the route continuous. Since the 1990s, a number of piecemeal relinquishments have been made. These are generally reflected in the length but not the termini. Former termini are not shown if they are along the current route, meaning that the route was simply extended. One Interstate Highway— Interstate 305—is defined only federally; the state calls it part of

US 50 U.S. Route 50 or U.S. Highway 50 (US 50) is a major east–west route of the U.S. Highway system, stretching from Interstate 80 (I-80) in West Sacramento, California, to Maryland Route 528 (MD 528) in Ocean City, Maryland, on the Atlantic ...

. It was signed as part of Business Interstate 80, the only state-maintained Interstate business route in California.

Primary Interstates

File:I-5 near Shasta.jpg, alt=Photograph, I-5 southbound approaching

Mount Shasta Mount Shasta ( ; Shasta people, Shasta: ''Waka-nunee-Tuki-wuki''; Karuk language, Karuk: ''Úytaahkoo'') is a Volcano#Volcanic activity, potentially active stratovolcano at the southern end of the Cascade Range in Siskiyou County, California. A ...

File:I-8 Alpine.jpg, alt=Photograph, I-8 in

Alpine Alpine may refer to any mountainous region. It may also refer to: Places Europe * Alps, a European mountain range ** Alpine states, which overlap with the European range Australia * Alpine, New South Wales, a Northern Village * Alpine National P ...

File:Wind farm from Interstate 10.jpg, alt=Photograph, I-10 eastbound with the

San Gorgonio Pass wind farm The San Gorgonio Pass wind farm is a wind farm that stretches from the eastern slope of the San Gorgonio Pass, near Cabazon, to North Palm Springs, on the western end of the Coachella Valley, in Riverside County, California. Flanked by Mount ...

in the background File:Interstate15 Ivanpah Valley.jpg, alt=Photograph, I-15 northbound descending into the

Ivanpah Valley The Ivanpah Valley is in southeastern California and southern Nevada in the United States. The valley is between the New York Mountains and the Ivanpah Mountains in San Bernardino County on the California side, and in Clark County on the Nevada ...

towards

Primm, Nevada Primm (formerly known as State Line) is an unincorporated town in Clark County, Nevada, United States, primarily notable for its position straddling Interstate 15 at the Nevada–California border. It sits on Ivanpah Dry Lake, which extends to ...

at the California-Nevada state line File:Interstate 40 in Fenner Valley 1.jpg, alt=Photograph, I-40 eastbound near Fenner File:I80Donnersummit.JPG, alt=Photograph, I-80 eastbound in the Sierra Nevada from the Yuba Gap overpass towards the western approach to

Donner Summit Donner Pass is a mountain pass in the northern Sierra Nevada, above Donner Lake and Donner Memorial State Park about west of Truckee, California. Like the Sierra Nevada themselves, the pass has a steep approach from the east and a gradual a ...

Auxiliary Interstates

File:Sep 09 215 Construction.jpg, alt=Photograph, Construction on I-215 between Inland Center Drive and Orange Show Road in

San Bernardino San Bernardino ( ) is a city in and the county seat of San Bernardino County, California, United States. Located in the Inland Empire region of Southern California, the city had a population of 222,101 in the 2020 census, making it the List of ...

File:Interstate 280 near Stanford p1130161.jpg, alt=Photograph, I-280 running along near

Stanford University Leland Stanford Junior University, commonly referred to as Stanford University, is a Private university, private research university in Stanford, California, United States. It was founded in 1885 by railroad magnate Leland Stanford (the eighth ...

File:The 405 in the Sepulveda Pass.JPG, alt=Photograph, Cars driving on I-405 through the

Sepulveda Pass Sepulveda Pass (elevation ) is a low mountain pass through the Santa Monica Mountains in Los Angeles. It is named after the Sepúlveda family of California, a prominent Californio family that owned the land where the pass lies. It connects ...

File:Kluft-Photo-Aerial-I580-Altamont-Pass-Img 0037.jpg, alt=Photograph, I-580 winding through the

Altamont Pass wind farm The Altamont Pass wind farm is located in the Altamont Pass of the Diablo Range in Northern California. It is one of the earliest wind farms in the United States. The first wind turbines were placed on the Altamont in the early 1980s by John Ec ...

File:I605 CA dv 26 north lg.jpg, alt=Photograph, I-605 northbound approaching its northern terminus with I-210 File:View from I-680 (2).jpg, alt=Photograph, I-680 northbound descending from Mission Pass File:Empty Freeway.jpg, alt=Photograph, An empty I-805 at its interchange with I-8 in San Diego's

Mission Valley Mission Valley is a wide river valley trending east–west in San Diego, California, United States, through which the San Diego River flows to the Pacific Ocean. For planning purposes the City of San Diego divides it into two neighborhoods: Mi ...

File:Harborfreeway2.jpg, Rush hour on I-110 in

Los Angeles Los Angeles, often referred to by its initials L.A., is the List of municipalities in California, most populous city in the U.S. state of California, and the commercial, Financial District, Los Angeles, financial, and Culture of Los Angeles, ...

Business Routes

Notes

References