The following is a list of tunnels in California.

• Altamont Corridor Express
  • (two) Union Pacific Railroad (formerly Western Pacific Railroad) in Niles Canyon, Alameda County: one 4,500 feet (1,400 m) long and the other 450 feet (140 m) long^[1]
• BART
  • Balboa Park station complex
  • Berkeley Hills Tunnel, rapid transit tunnel, BART beneath Grizzly Peak between Orinda and Oakland
  • Berkeley Subway, beneath Berkeley
  • Broadway Subway in Oakland, including the Oakland Wye
  • Fremont Central Park Subway, underneath Lake Elizabeth
  • Market Street subway twin level rapid transit and light rail tunnel beneath Market Street in San Francisco (shared with Muni Metro)
  • Milpitas station
  • Lundy/Sierra tunnel
  • Silicon Valley BART extension Phase 3 (planned)
  • Transbay Tube, rapid transit tunnel, BART beneath San Francisco Bay between Oakland and San Francisco
  • San Francisco International Airport extension
• Caltrain
  • (five) Bayshore Cutoff, originally built by the Southern Pacific railroad, tunnel 5 abandoned in 1956
  • The Portal (proposed)
    • Salesforce Transit Center train box
• Los Angeles Metro Rail
  • (three) K Line (under construction)
  • Figueroa Tunnel, on the E Line
  • Flower Street tunnel, carrying the A and E Lines to the 7th Street/Metro Center station
  • L Line subway, between Indiana and Pico/Aliso stations
  • Los Angeles Subway, including the B Line and D Line
  • Regional Connector
• Metrolink
  • San Fernando Tunnel, rail tunnel, Union Pacific Railroad (formerly Southern Pacific Railroad), Santa Clarita^[2]
  • (three) Simi Valley Tunnels/Santa Susana Tunnels, rail tunnels, Union Pacific Railroad (formerly Southern Pacific Railroad), between Los Angeles and Simi Valley through the Santa Susana Mountains; the longest and westernmost is Tunnel No. 26^[3]
• San Francisco Municipal Railway (Muni Metro)
  • Central Subway
  • Sunset Tunnel, light rail tunnel beneath Buena Vista Park
  • Twin Peaks Tunnel, light rail tunnel beneath Twin Peaks
  • Market Street subway twin level rapid transit and light rail tunnel beneath Market Street in San Francisco (shared with BART)
• Sonoma–Marin Area Rail Transit
  • Cal Park Hill Tunnel, beneath California Park, also features a pedestrian/bicycle path
  • Puerto Suello Hill Tunnel, commuter rail tunnel
• SDSU Transit Center, the only subway station in the San Diego Trolley system
• VTA light rail tunnel under San Jose Diridon station

• Belmont Tunnel/Toluca Substation and Yard
• (five) North Pacific Coast Railroad tunnels, including:
  • Alto Tunnel
• Tunnel 8, former Northwestern Pacific Railroad tunnel
• Shepherd Canyon, used by the Sacramento Northern Railway
• (five) Wrights, Laurel, Zayante, Tunnel 5, and Mountain Charlie Tunnels; built by the South Pacific Coast Railroad (Tunnel 7 daylighted c. 1950s)

• Fort Mason Tunnel, former rail tunnel beneath Fort Mason, San Francisco
• Point Richmond Tunnel, carrying BNSF freight parallel to the road tunnel in Point Richmond
• Summit Tunnel (Tunnel No. 6), abandoned rail tunnel, Central Pacific Railroad, one of a number through the Donner Pass area of the Sierra Nevada^[4]
• The Big Hole, Tunnel No. 41, built to replace Tunnel No. 6 through the Donner Pass and carrying the Union Pacific Railroad
• (34) Feather River Route, including:
  • Chilcoot Tunnel
  • Spring Garden Tunnel
  • Keddie Wye, tunnels Tunnel No. 31 and No. 32 in the wye complex
• Mission Tunnel, below Mission Santa Cruz and used by the Santa Cruz, Big Trees and Pacific Railway
• (three) BNSF Gateway Subdivision
• (three) BNSF Stockton Subdivision, including:
  • Franklin Tunnel
• (six) Union Pacific Coast Subdivision
  • Tunnel No. 6 (Coast Line)
• Tehachapi Loop Tunnel, rail tunnel, 1876, Union Pacific Railroad (formerly, Southern Pacific Railroad), just north of State Route 58 between Tehachapi and Bakersfield

• (two) California Western Railroad, popularly called the Skunk Train

• Collier Tunnel, Redwood Highway (US 199), Del Norte County
• Dornan Tunnel,^[5] carrying Gerrard Avenue in Point Richmond parallel to the rail tunnel
• Escondido Freeway (SR 15), cut-and-cover tunnel between Polk and Orange Avenues in East San Diego (Teralta Park covers the freeway)
• Feather River Highway (SR-70), three tunnels, Feather River Canyon
• Gaviota Tunnel, northbound US 101, Santa Barbara County
• Harry Crabb Tunnel, ramp to eastbound Interstate 80 (Alan S. Hart Freeway) from northbound Sunrise Avenue (south of Douglas Boulevard) in Roseville^[6]
• John F. Foran Freeway (I-280), (southbound only) at its interchange with the 19th Avenue (SR 1) in Daly City
• Lighthouse Avenue Tunnel,^[7][8] Monterey
• Tom Lantos Tunnels/Devil's Slide Tunnels, twin tunnels, SR 1 beneath Devil's Slide between Pacifica and Montara
• Tunnels to Nowhere, two tunnels, Shoemaker Canyon Road (unpaved), San Gabriel Mountains
• Big Oak Flat Road, three tunnels, Yosemite National Park
• Wawona Tunnel, Wawona Road (SR 41), Yosemite National Park, the longest road tunnel in California at 4,233 feet (1,290 m)

• 11th Street Tunnel, under the Oakland Museum of California in Oakland
• Caldecott Tunnel, quad tunnels, SR 24 beneath Grizzly Peak between Orinda and Oakland
• Northbrae Tunnel, former East Bay Electric Lines rail tunnel, current road tunnel joining Solano Avenue and Sutter Street beneath Marin Circle, Berkeley
• Posey and Webster Street Tubes, twin immersed tubes, SR 61 beneath the Oakland Estuary between Alameda and Oakland

• Airport Tunnel, twin tunnels, Sepulveda Boulevard (SR 1) beneath Runways 7L/25R and 7R/25L at Los Angeles International Airport, Los Angeles
• Angeles Crest Highway (State Route 2), two sets of tunnels in the San Gabriel Mountains National Monument northeast Los Angeles County between La Cañada Flintridge and Wrightwood
• Angeles Forest Highway Tunnel/Singing Springs Tunnel/Hidden Springs Tunnel, Angeles Forest Highway/County Road N3, San Gabriel Mountains National Monument, north Los Angeles County between La Cañada Flintridge and Palmdale
• Broadway Tunnel extended Broadway further north, later demolished
• Kanan Dume Tunnel, north of Malibu
• Malibu Canyon Tunnel
• Figueroa Street Tunnels, northbound Arroyo Seco Parkway (SR 110), four tunnels beneath Elysian Park, Los Angeles
• Foothill Freeway (I-210)
  • Cut-and-cover tunnel between Glendale Freeway and Angeles Crest Highway (both part of State Highway 2) in La Cañada Flintridge (Memorial Park covers the freeway)
  • Two short tunnels (eastbound only) under SR 710 and Ventura Freeway (SR 134) in Pasadena
• Griffith Park Tunnel, Vermont Canyon Road/Mount Hollywood Drive in Griffith Park, Los Angeles
• Long Beach Airport tunnels, two sets of twin tunnels for Lakewood Boulevard (SR 19) and Spring Street under runway 12/30 at Long Beach Airport, Long Beach
• McClure Tunnel, SR 1 located at the western terminus of I-10 in Santa Monica
• Mount Baldy Road, two tunnels, north of Claremont
• Newhall Pass Tunnels, two tunnels about 550 feet (170 m) each, southbound truck bypass lanes of the Golden State Freeway (I‑5), in Santa Clarita and Los Angeles^[9]
• Orange Freeway (SR 57), (northbound only) at its interchange with the Pomona Freeway (SR 60) in Diamond Bar
• Santa Ana Freeway portion of US 101 (northbound only), at its interchange with the San Bernardino Freeway (SR 10) in downtown Los Angeles
• Second Street Tunnel, beneath Bunker Hill, downtown Los Angeles
• Third Street Tunnel, beneath Bunker Hill, downtown Los Angeles
• Sepulveda Boulevard Tunnel, Sepulveda Boulevard under Mulholland Drive at the north end of Sepulveda Pass, Los Angeles
• Van Nuys Airport Tunnel, twin tunnels, Sherman Way under runway 16R/34L at Van Nuys Airport, west San Fernando Valley, Los Angeles

• Baker-Barry Tunnel, single lane tunnel, Bunker Rd, Sausalito
• Robin Williams Tunnel/Waldo Tunnel, twin tunnels, US 101 and SR 1, Sausalito

• Main Street under the Santa Ana Freeway (I‑5) in Tustin, California
• SR 133 segment of the Eastern Transportation Corridor toll road, (northbound only) at its interchange with the SR 241 (Foothill Transportation Corridor) in Irvine
• SR 261 segment of the Eastern Transportation Corridor toll road, (northbound only) at its interchange with the SR 241 (Eastern Transportation Corridor) in Orange

• Broadway Tunnel, twin tunnels, Broadway beneath Russian Hill
• MacArthur Tunnel, SR 1 beneath the Presidio of San Francisco (Golden Gate National Recreation Area)
• Masonic Tunnel, carrying Geary Boulevard under Masonic Avenue
• Presidio Parkway, US 101 through the Presidio of San Francisco (replacement for the elevated Doyle Drive)
• Stockton Street Tunnel, beneath a portion of Chinatown
• Yerba Buena Tunnel, twin tunnels, I-80 near the middle of the San Francisco–Oakland Bay Bridge complex, Yerba Buena Island

• Kennedy Tunnel, former road above the extant Caldecott Tunnel (see above)

• Angeles Tunnel
• Claremont Tunnel
• Hetch Hetchy Coast Range tunnel
• (three) Inland Feeder
  • Arrowhead West Tunnel
  • Arrowhead East Tunnel
  • Riverside Badlands Tunnel
• Mile Rock
• San Jacinto Tunnel
• South Bay Aqueduct
• Trinity Diversion Tunnel: a 10.7 mile tunnel diverting water from the Trinity Basin to the Sacramento Valley.

• Burro Schmidt Tunnel, mining tunnel, east of Red Rock Canyon State Park, eastern Kern County

• SpaceX constructed a 1.4 Mile test tunnel underneath the parking lot of its Hawthorne plant for experimental transportation technology.
• United States Airforce Plant 42 in Palmdale is rumored to have an underground network of tunnels connecting to nearby defense plants including Lockheed's Skunk works.
• Ft. McArthur Tunnel Complex: an abandoned World War II network connecting fortifications in San Pedro, CA.^[10]
• The Lawson Adit is a tunnel constructed underneath UC Berkeley into the Berkeley Hills in the early 1900s for student mining research.^[11]
• US Dept. of Defense Tunnel Warfare Center, China Lake^[12][13]
• The Stanford Linear Accelerator operates in a 10,000-foot concrete tunnel, 25 feet underground.
• Vandenberg Space Force Base has a number of underground tunnels to support rocket launch operations.

• List of tunnels in the United States