# List of Interstate Highways in California

This is a list of Interstate Highways in the U.S. state of California that have existed since the 1964 renumbering. It includes routes defined by the California State Legislature 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 (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/I-580 concurrency, known as the Eastshore Freeway, 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. It was signed as part of Business Interstate 80, the only state-maintained Interstate business route in California.

## Primary Interstates

| Number | Length (mi) | Length (km) | Southern or western terminus | Northern or eastern terminus | Formed | Removed | Notes |
| I-5 | 796.432 | 1,281.733 | Mexican border in San Ysidro, San Diego | I-5 at the Oregon state line | 01947-01-011947 | current | |
| I-5E | — | — | I-5 near Tracy | I-5 near Dunnigan | 01957-01-011957 | 01970-03-141970 | Former designation of I-5 when I-5W existed |
| I-5W | — | — | I-5 near Tracy | I-5 near Dunnigan | 01957-01-011957 | 01970-03-141970 | Former designation of I-580 and I-505 |
| I-7 | 302 | 486 | I-5 at Wheeler Ridge | I-5 in Stockton | proposed | — | Caltrans has proposed I-7 or I-9 for SR 99 in central California |
| I-8 | 171.98 | 276.77 | Nimitz Boulevard, Sunset Cliffs Boulevard in San Diego | I-8 at the Arizona state line | 01964-01-011964 | current | Westernmost segment between Nimitz Boulevard/Sunset Cliffs Boulevard and I-5 is not officially recognized as an Interstate by the FHWA |
| I-9 | 302 | 486 | I-5 at Wheeler Ridge | I-5 in Stockton | proposed | — | Caltrans has proposed I-7 or I-9 for SR 99 in central California |
| I-10 | 243.31 | 391.57 | SR 1 in Santa Monica | I-10 at the Arizona state line | 01947-01-011947 | current | Route 10, as defined by the state, is broken into two segments at the East Los Angeles Interchange; traffic is directed via I-5 to connect the two; the portion between I-5 and US 101 not signed |
| I-15 | 287.26 | 462.30 | I-8 in San Diego | I-15 at the Nevada state line | 01957-01-011957 | current | |
| I-15E | — | — | I-15 in Temecula | I-15 in Devore, California | 01973-01-011973 | 01982-01-011982 | Renumbered from I-215 in 1973 and back to I-215 in 1982 |
| I-15W | — | — | I-15 in Murrieta | I-15 in Devore, California | 01972-01-011972 | 01974-01-011974 | Temporary Signage along current I-15 |
| I-40 | 154.623 | 248.842 | I-15 in Barstow | I-40 at the Arizona state line | 01947-01-011947 | current | |
| I-80 | 205.07 | 330.03 | US 101 in San Francisco | I-80 at the Nevada state line | 01947-01-011947 | current | Westernmost segment between US 101 and the Bay Bridge is not officially recognized as an Interstate by the FHWA |
| Former Proposed and unbuilt ||||||||
* I-5 southbound approaching Mount Shasta
* I-8 in Alpine
* I-10 eastbound with the San Gorgonio Pass wind farm in the background
* I-15 northbound descending into the Ivanpah Valley towards Primm, Nevada at the California-Nevada state line
* I-40 eastbound near Fenner
* I-80 eastbound in the Sierra Nevada from the Yuba Gap overpass towards the western approach to Donner Summit

## Auxiliary Interstates

| Number | Length (mi) | Length (km) | Southern or western terminus | Northern or eastern terminus | Formed | Removed | Notes |
| I-105 | 18.82 | 30.29 | SR 1 in El Segundo | I-605 in Norwalk | 01982-01-011982 | current | Right-of-way formerly planned as part of SR 42 |
| I-105 | — | — | I-5 in East Los Angeles | US 101 in Los Angeles | 01964-01-011964 | 01968-01-011968 | Renumbered as US 101; part of East Los Angeles Interchange |
| I-110 | 23.73 | 38.19 | SR 47 in San Pedro | I-10 in Los Angeles | 01978-01-011978 | current | Former routing of US 6/SR 11 |
| I-110 | — | — | I-10/I-5 in East Los Angeles | US 101 in Los Angeles | 01964-01-011964 | 01968-01-011968 | Deleted from highway system; part of East Los Angeles Interchange |
| I-180 | — | — | US 101 in San Rafael | I-80 in Berkeley | 01981-01-011981 | 01991-01-011991 | Former designation of I-580 |
| I-205 | 12.973 | 20.878 | I-580 near Tracy | I-5 near Manteca | 01970-01-011970 | current | Formerly part of US 50 |
| I-210 | 44.90 | 72.26 | I-5 in Los Angeles | SR 57 in Glendora | 01964-01-011964 | current | Entire length of SR 210 to be renumbered to I-210. SR 57 from I-10 to I-210/SR 210 is an unsigned designation of I-210 used by the FHWA and AASHTO |
| I-215 | 55.060 | 88.610 | I-15 in Murrieta | I-15 in San Bernardino | 01982-01-011982 | current | Formerly I-15E and SR 215 |
| I-238 | 2.126 | 3.421 | I-580 in Castro Valley | I-880 in San Leandro | 01983-01-011983 | current | Technically a spur of I-80; only violation in the Interstate system |
| I-280 | 57.510 | 92.553 | US 101/I-680 in San Jose | King and 5th Streets in San Francisco | 01955-01-011955 | current | |
| I-305 | 5.64 | 9.08 | I-80 in West Sacramento | SR 99 in Sacramento | 01981-01-011981 | current | Unsigned designation used by the FHWA and the AASHTO; signed as part of US 50 |
| I-380 | 1.67 | 2.69 | I-280 in San Bruno | US 101 in South San Francisco | 01964-01-011964 | current | Formerly proposed to be extended west to SR 1 and east along the Southern Crossing to I-880 |
| I-405 | 72.415 | 116.541 | I-5 in Irvine | I-5 near San Fernando | 01964-01-011964 | current | |
| I-480 | — | — | US 101 in San Francisco | I-80 in San Francisco | 01957-01-011957 | 01968-01-011968 | Demoted to state highway in 1968 |
| I-505 | 32.99 | 53.09 | I-80 in Vacaville | I-5 near Dunnigan | 01977-01-011977 | current | Formerly part of I-5W |
| I-580 | 75.550 | 121.586 | US 101 in San Rafael | I-5 near Tracy | 01947-01-011947 | current | Various segments formerly part of US 50, I-5W or SR 17 |
| I-605 | 27.40 | 44.10 | I-405/SR 22 in Seal Beach | I-210 in Irwindale | 01964-01-011964 | current | |
| I-680 | 70.536 | 113.517 | US 101/I-280 in San Jose | I-80 in Fairfield | 01976-01-011976 | current | Formerly part of SR 21 |
| I-680 | 6.759 | 10.878 | I-80 in Vallejo | I-680 in Benicia | 01955-01-011955 | 01976-01-011976 | Renumbered as I-780 |
| I-710 | 24.249 | 39.025 | SR 47 in Long Beach | Valley Boulevard in Alhambra | 01984-01-011984 | current | Formerly part of SR 7. The portions north of I-10 and south of SR 1 are not officially recognized as Interstates by the FHWA |
| I-780 | 6.759 | 10.878 | I-80 in Vallejo | I-680 in Benicia | 01976-01-011976 | current | Formerly part of I-680 |
| I-805 | 28.016 | 45.087 | I-5 in San Ysidro, San Diego | I-5 in Sorrento Valley, San Diego | 01959-01-011959 | current | |
| I-880 | 45.698 | 73.544 | I-280/SR 17 in San Jose | I-80/I-580 in Oakland | 01984-01-011984 | current | Formerly part of SR 17 |
| I-905 | 8.964 | 14.426 | I-5 in San Diego | Mexican border near Otay Mesa | proposed | — | Currently SR 905 |
| I-980 | 2.027 | 3.262 | I-880 in Oakland | I-580/SR 24 in Oakland | 01981-01-011981 | current | Right-of-way formerly part of SR 24 |
| Former Proposed and unbuilt ||||||||
* Construction on I-215 between Inland Center Drive and Orange Show Road in San Bernardino
* I-280 running along near Stanford University
* Cars driving on I-405 through the Sepulveda Pass
* I-580 winding through the Altamont Pass wind farm
* I-605 northbound approaching its northern terminus with I-210
* I-680 northbound descending from Mission Pass
* An empty I-805 at its interchange with I-8 in San Diego's Mission Valley
* Rush hour on I-110 in Los Angeles

## Business Routes

| Number | Length (mi) | Length (km) | Southern or western terminus | Northern or eastern terminus | Formed | Removed | Notes |
| I-5 BL | — | — | I-5 in San Ysidro | I-5 in Chula Vista | 01960-01-01c. 1960 | 01990-01-011990 | old US 101 along Beyer Boulevard, Broadway, Harbor Drive, and Pacific Highway. |
| I-5 BL | — | — | I-5 in San Diego | I-5 in San Diego | — | 02005-01-012005 | old US 101 along Mission Bay Drive. |
| I-5 BL | — | — | I-5 in San Diego | I-5 in Oceanside | 01960-01-01c. 1960 | current | old US 101 along Coast Highway (CR S-21). |
| I-5 BL | — | — | I-5 in Glendale | I-5 in Granada Hills | 01970-01-01c. 1970 | 01980-01-011980 | travels along San Fernando Road (old US 99 and US 6). |
| I-5 BL | — | — | I-5 in Woodland | I-5 in Woodland | 01970-01-01c. 1970 | 01980-01-011980 | Between I-5 Exits 537 and 540. |
| I-5 BL | 1.1 | 1.8 | I-5 in Arbuckle | I-5 in Arbuckle | — | — | Between I-5 Exits 566 and 567. |
| I-5 BL | — | — | I-5 in Williams | I-5 in Maxwell | — | — | Between I-5 Exits 575 and 588. |
| I-5 BL | — | — | I-5 in Willows | I-5 in Orland | — | — | Between I-5 Exits 601 and 621. |
| I-5 BL | 4.2 | 6.8 | I-5 in Red Bluff | I-5 in Red Bluff | — | — | Between I-5 Exits 647 and 651. |
| I-5 BL | — | — | I-5 in Cottonwood | I-5 in Cottonwood | — | — | old US 99 between I-5 Exits 662 and 665. |
| I-5 BL | 3.7 | 6.0 | I-5 in Dunsmuir | I-5 in Dunsmuir | — | — | old US 99 along Dunsmuir Avenue between I-5 Exits 729 and 732. |
| I-5 BL | 3.8 | 6.1 | I-5 in Mount Shasta | I-5 in Mount Shasta | — | — | Between I-5 Exits 647 and 651. |
| I-5 BL | — | — | I-5 in Weed | I-5 in Weed | — | — | old US 99 between I-5 Exits 747 and 748. |
| I-5 BL | — | — | I-5 in Yreka | I-5 in Yreka | — | — | Between I-5 Exits 773 and 776. |
| I-8 BL | — | — | I-8 in San Diego | I-8 in La Mesa | 01970-01-01c. 1970 | 01995-01-011995 | Between I-8 Exits 4B-C and 13A (Washington Street, Normal Street, El Cajon Boulevard) |
| I-8 BL | 8.15 | 13.12 | I-8 in El Cajon | I-8 in Lakeside | — | — | Between I-8 Exits 15 and 23 |
| I-8 BL | 4.25 | 6.84 | I-8 in Alpine | I-8 in Alpine | — | — | former US 80 along Alpine Drive between I-8 Exits 30 and 33 |
| I-8 BL | 4.25 | 6.84 | I-8 in El Centro | I-8 in El Centro | — | — | Between I-8 Exits 114 and 115 |
| I-8 BL | 2.18 | 3.51 | I-8 in Alpine | Bus.I-8 in Yuma, AZ | — | — | Historic US 80 between I-8 Exit 170 and AZ line |
| I-10 BL | 7.9 | 12.7 | I-10 in Pomona | I-10 in Ontario | — | — | former US 70/US 99 between I-10 Exits 42B and 55A |
| I-10 BL | — | — | I-10 in Fontana | I-10 in Colton | — | — | former US 70/US 99 between I-10 Exits 59 and 71 |
| I-10 BL | — | — | I-10 in Colton | I-10 in Coachella | — | — | former US 60/US 70/US 99 between I-10 Exits 139 and 146 |
| I-10 BL | 7.9 | 12.7 | I-10 in Blythe | I-10 in Blythe | — | — | former US 60/US 70 between I-10 Exits 236 and 243 |
| I-15 BL | — | — | I-15 in Escondido | I-15 in Escondido | — | — | former US 395 between I-15 Exits 28 and 34 |
| I-15 BL | — | — | I-15 in Lake Elsinore | I-15 in Lake Elsinore | — | — | Between I-15 Exits 73 and 75 |
| I-15 BL | — | — | I-15 in Norco | I-15 in Norco | — | — | Between I-15 Exits 98 and 100 |
| I-15 BL | — | — | I-15 in Victorville | I-15 in Victorville | — | — | Historic US 66/US 91 between I-15 Exits 150 and 153A |
| I-15 BL | — | — | I-15 in Barstow | I-15 in Barstow | — | — | Historic US 66/US 91 between I-15 Exits 181 and 184B |
| I-15 BL | 3.6 | 5.8 | I-15 in Baker | I-15 in Baker | — | — | Old US 91/US 466 between I-15 Exits 245 and 248 |
| I-40 BL | 3.4 | 5.5 | I-40 in Needles | I-40 in Needles | — | — | Old US 66/US 95 between I-40 Exits 141 and 145 |
| I-80 BL | 13.82 | 22.24 | I-80 in West Sacramento | I-80 in Sacramento | 01980-01-01c. 1980 | current | Between I-80 Exits 82 and 95 |
| I-205 BL | — | — | I-205 in Tracy | I-5 in Lathrop | — | — | Old US 50 between I-205 Exit 4 and I-5 Exit 458B |
| Former Proposed and unbuilt ||||||||