List of Interstate Highways in California

Interstate Highways in California
Standard Interstate signage in California
Highway names
Interstates:	Interstate XX (I-XX)
US Routes:	U.S. Route XX (US XX)
State:	State Route XX (SR XX)
System links
State highways in California Interstate U.S. State Pre-1964 History Unconstructed Deleted Freeway Scenic

This is a list of Interstates in the U.S. state of California that have existed since the 1964 renumbering. It includes routes that were defined by the California State Legislature but never built, as well as routes that have been 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^[1][2]) 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.
• If a route was renumbered, the old or new number is given in the "notes" column.
• The years are when legislative action was taken, not when real-world changes were made.
• Concurrences 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 is signed as part of Business Interstate 80, the only state-maintained Interstate business route in California.

Primary Interstates

Number	Length (mi)[3][lower-alpha 1]	Length (km)	Southern or western terminus	Northern or eastern terminus	Formed	Removed	Notes
I-5	796.432	1,281.733	Border with Mexico in San Ysidro, San Diego	Oregon state line	1947	current
I-5W	—	—	I-5 near Tracy	I-5 near Dunnigan	1957	1970	Former designation of I-580 and I-505
I-8	171.98	276.77	Nimitz Boulevard, Sunset Cliffs Boulevard in San Diego	Arizona state line	1964	current
Future I‑9	—	—	I-5 in Wheeler Ridge	I-5 in Stockton or Sacramento	proposed	—	Routed along current SR 99; could be designated I-7
I-10	243.31[lower-alpha 2]	391.57	SR 1 in Santa Monica	Arizona state line	1947	current	I-10 exists in two segments; traffic is directed via I-5 through downtown Los Angeles to connect the two; the portion of I-10 between I-5 and US 101 not signed
I-15	287.26[lower-alpha 3]	462.30	I-8 in San Diego	Nevada state line	1957	current
I-15E	—	—	I-15 in Temecula, California	I-15 in Devore, California	1973	1982	Renumbered from I-215 in 1973 and back to I-215 in 1982
I-40	154.623	248.842	I-15 in Barstow	Arizona state line	1947	current
I-80	205.07	330.03	US 101 in San Francisco	Nevada state line	1947	current	Westernmost segment between US 101 and the Bay Bridge is not federally recognized as an Interstate
Former       Future

Auxiliary Interstates

Number	Length (mi)[3][lower-alpha 1]	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	1982	current	Right-of-way formerly planned as part of SR 42
I-110	23.73[lower-alpha 3]	38.19	SR 47 in San Pedro	I-10 in Los Angeles	1978	current	Former routing of US 6 / SR 11
I-180	—	—	US 101 in San Rafael	I-80 in Berkeley	1981	1991	Former designation of I-580
I-205	12.973	20.878	I-580 near Tracy	I-5 near Manteca	1970	current	Formerly part of US 50
I-210	44.90[lower-alpha 3]	72.26	I-5 in Los Angeles	SR 57 in Glendora	1964	current
I-215	55.060	88.610	I-15 in Murrieta	I-15 in San Bernardino	1982	current	Formerly I-15E and SR 215
I-238	2.126[lower-alpha 3]	3.421	I-580 in Castro Valley	I-880 in San Leandro	1983	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	1955	current
I-305	5.64	9.08	I-80 in West Sacramento	SR 99 in Sacramento	1926	current	Only defined federally; signed as part of US 50 / Business I-80
I-380	1.670	2.688	I-280 in San Bruno	US 101 in South San Francisco	1964	current
I-405	72.415	116.541	I-5 in Irvine	I-5 near San Fernando	1964	current
I-480	—	—	US 101 in San Francisco	I-80 in San Francisco	1957	1968	Demoted to state highway in 1968
I-505	32.99	53.09	I-80 in Vacaville	I-5 near Dunnigan	1977	current	Formerly part of I-5W
I-580	75.550	121.586	US 101 in San Rafael	I-5 near Tracy	1947	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	1964	current
I-680	70.536	113.517	US 101 / I-280 in San Jose	I-80 in Fairfield	1955	current	Formerly part of SR 21
I-710	24.249[lower-alpha 4]	39.025	SR 47 in Long Beach	Valley Boulevard in Alhambra	1984	current	Formerly part of SR 7. The Seaside Freeway portion is unsigned and not federally recognized as an Interstate.
I-780	6.759	10.878	I-80 in Vallejo	I-680 in Benicia	1976	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	1959	current
I-880	45.698	73.544	I-280 / SR 17 in San Jose	I-80 / I-580 in Oakland	1984	current	Formerly part of SR 17
I-905	8.964	14.426	I-5 in San Diego	Border with Mexico near Otay Mesa	proposed	—
I-980	2.027	3.262	I-880 in Oakland	I-580 / SR 24 in Oakland	1981	current	Right-of-way formerly part of SR 24
Former       Future

See also

• California Roads portal

Notes

1. Lengths rounded to the nearest mile or tenth-mile are estimated from various sources including Google Maps.
2. This route is broken into pieces, and the length does not reflect the overlaps that would be required to make the route continuous.
3. Part of one of the contiguous routes that is partially signed as an Interstate Highway, while the remaining segment is signed as a state highway.
4. This route is broken into pieces due to a gap in the description, unfilled by any route.

References

1. "Section 231". California Streets and Highways Code – via Wikisource.
2. California Department of Transportation. "Other State Highway Routes". Sacramento: California Department of Transportation.
3. California Department of Transportation. "State Truck Route List" (XLS file). Sacramento: California Department of Transportation. Retrieved February 2008.