Interstate 280 (California)

Interstate 280 (I-280) is a 57 mile (92 km) long interstate freeway in the San Francisco Bay Area metropolitan area of Northern California. The freeway runs from the US 101/Interstate 680 interchange in San Jose to the South of Market area in San Francisco, just south of AT&T Park, home of the San Francisco Giants baseball team. It and I-680 form a partial beltway around the Bay Area.

I-280 beginning at its interchange with State Route 1 in Daly City was built and dedicated as the Junipero Serra Freeway. One of the dedication signs (in Daly City) still indicates that the Junipero Serra Freeway is known as the "World's Most Beautiful Freeway" due to its scenic route though the San Francisco Peninsula. The portion of Interstate 280 between U.S. 101 and Interstate 880 is also named the Sinclair Freeway.

This route is part of the California Freeway and Expressway System and is eligible for the State Scenic Highway System.

Route description

In between San Jose and San Francisco, Interstate 280 passes through Santa Clara, Cupertino, Los Altos and Los Altos Hills before it settles along its scenic route just to the west of the cities of the San Francisco Peninsula in San Mateo County and just to the east of the Santa Cruz Mountains. I-280 re-emerges in a decidedly urbanized area in the city of San Bruno, passing through South San Francisco and Daly City before it runs across a southeastern swath of the city of San Francisco on the way to its northern terminus.

Major cities
Bolded cities are officially-designated control cities for signs

The segment of the Junipero Serra Freeway between Cupertino and Daly City, has been called the "World's Most Beautiful Freeway" since its dedication in the 1960s. Drivers along this portion of Interstate 280 are treated to scenic views of the Santa Cruz Mountains to the west and San Francisco Bay to the east, and are isolated by hills from the cities to the east. Through much of this segment, the freeway is actually running just inside the eastern rim of the canyon of the San Andreas Fault. A particularly attractive six mile (ten kilometer) stretch of the freeway from Hillsborough to Belmont provides a beautiful look at Crystal Springs Reservoir, formed by water piped hundreds of miles from Hetch Hetchy Valley in Yosemite National Park, filling the bottom of the fault canyon.

For nearly all of its length, Interstate 280 runs roughly parallel and several miles to the west of US 101 (the Bayshore Freeway). Both freeways are north-south routes connecting San Jose with San Francisco; however, unlike I-280, the route that US 101 takes between the two cities goes entirely through urbanized areas. The majority of the population of the San Francisco Peninsula lives somewhere between Interstate 280 and US 101.

I-280 never intersects with Interstate 80, its parent interstate. The northern terminus of I-280 is within about a mile of I-80's western terminus (at the approach to the San Francisco – Oakland Bay Bridge), but the two interstates do not actually intersect. Although San Francisco has had several opportunities to connect I-280 to I-80, it has chosen to use the money for other purposes. Connecting the two freeways is considered to be politically and financially infeasible at this time, due to the city's strong anti-freeway stance. Instead, 280's northernmost extension primarily functions as a spur into Downtown San Francisco, as suggested by signage on northbound US 101 at its San Francisco interchange with 280 (see history section below).

Most of Interstate 280, from San Jose to Daly City, is designated as the Junipero Serra Freeway in honor of Spanish missionary Junípero Serra, who founded many of California's missions in the 18th century. A 26-foot (8 meter) high faux-sandstone statue of Father Serra kneeling and pointing over the freeway is located at a highway rest area just north of the Highway 92 intersection between the Bunker Hill Drive and Black Mountain Road exits on northbound I-280 in Hillsborough, and can be clearly seen by drivers in both directions. The segment of Interstate 280 north of Route 1 in San Francisco was originally named the Southern Freeway, but has since been officially renamed the John F. Foran Freeway. However, most San Franciscans still refer to it as the Southern Freeway. The section of I-280 between the James Lick Freeway and its end at Third Street and King Street is called the Southern Embarcadero Freeway.

Major intersections include US 101 and State Route 1 in San Francisco, Interstate 380 in San Bruno, and Interstate 880 and 680 and US 101 in San Jose.

The Junipero Serra Freeway is Route 280 from Route 1 in San Francisco to Route 17, as named by Assembly Concurrent Resolution 140, Chapter 208 in 1967.


Interstate 280 was added to the Interstate Highway System on September 15, 1955 as a route from San Jose north to San Francisco. This ran along the present alignment of I-280 south of San Francisco, but in San Francisco it ran north parallel to State Route 1, past the planned west end of Interstate 80, to the south approach to the Golden Gate Bridge. At that point, Interstate 480 began and headed east on Doyle Drive (U.S. Route 101), the Golden Gate Freeway, and onto the Embarcadero Freeway to reach the San Francisco – Oakland Bay Bridge. I-480 would continue south on the never-built Southern Embarcadero Freeway to meet the Southern Freeway (now I-280), and meet up with I-280 again near the Alemany Maze, which served as the 101A Bypass until I-280 was built. The I-280 number was approved on November 10, 1958.

In the 1964 renumbering, the Route 280 designation was officially applied to the planned route. This replaced SR 1 in San Francisco; the new SR 1 alignment turned northeast where I-280 now runs, quickly ending at State Route 82 (San Jose Avenue/Alemany Boulevard). SR 1 however continued to be signed along its former (and current) alignment, which had not been upgraded to freeway standards.

A realignment approved January 1968 took I-280 onto its current route. This ran along what had been SR 1, SR 82, State Route 87 and I-480 (downgraded to a State Route then), ending at Interstate 80 at the west end of the Bay Bridge. This change was made on the state level in 1968, restoring SR 1 to its current alignment and truncating SR 82, SR 87 and SR 480.

The section of I-280 between SR 92 (San Mateo) and SR 84 (Woodside) was not completed until the 1970s. Until then, traffic was routed on Cañada road between the two ends.

The short piece of I-280 between 3rd Street and SR 480 in downtown San Francisco was never built, and the piece from 3rd Street south to U.S. Route 101 was reconstructed after it was damaged by the 1989 Loma Prieta earthquake. The piece between SR 480 and I-80 was torn down along with the rest of the Embarcadero Freeway; all that remains of the I-80 interchange is a few ramp stubs, which will be removed as part of the San Francisco – Oakland Bay Bridge Western Approach reconstruction project.

Exit list

Note: Except where prefixed with a letter, postmiles were measured in 1964, based on the alignment as it existed at that time, and do not necessarily reflect current mileage. The numbers reset at county lines; the start and end postmiles in each county are given in the county column.
County Location Postmile
# Destinations Notes
Santa Clara
SCL R0.00-20.63
San Jose R0.00 Continuation beyond US 101
R0.00 Southbound exit and northbound entrance
R0.37 1A McLaughlin Avenue Southbound exit and northbound entrance
R1.29 1B 11th Street, 10th Street Signed as exit 1 northbound
R1.99 2A Signed as exit 2 northbound
2B Almaden Boulevard, Vine Street Southbound exit and northbound entrance
R2.52 3A
R2.88 3B Bird Avenue
R3.76 4 Race Street, Southwest Expressway Northbound exit and southbound entrance
R3.99 4 Meridian Avenue Southbound exit and northbound entrance
L4.66 5A Leigh Avenue, Bascom Avenue
L5.41 5B Signed as exits 5B (south) and 5C (north) northbound
4.57 6 Winchester Boulevard – Campbell Southbound exit and northbound entrance
5.95 7 Saratoga Avenue – Saratoga
9 CR G2/Lawrence Expressway, Stevens Creek Boulevard
Cupertino 8.38 10 Wolfe Road
9.43 11 De Anza Boulevard
10.74 12 Signed as exits 12A (north) and 12B (south)
Los Altos 11.45 13 Foothill Expressway, Grant Road
14.10 15 Magdalena Avenue
Los Altos Hills 15.05 16 El Monte Road, Moody Road
18.38 20 Page Mill Road, Arastradero Road – Palo Alto
20.61 22 Alpine Road – Portola Valley
San Mateo
R1.61 24 Sand Hill RoadMenlo Park
Woodside R3.34 25
R4.65 27 Farm Hill Boulevard
R6.60 Canada Road No exit ramps
6.65 29 Edgewood Road
10.87 33 Southbound exit to SR 92 west is via exit 34
R12.32 34 South end of SR 35 overlap
Hillsborough R14.22 36 Black Mountain Road, Hayne Road
R17.16 39 Trousdale Drive – Burlingame
Millbrae R17.92 40 Millbrae Avenue Northbound exit and southbound entrance
R18.52 41 Larkspur Drive, Millbrae Avenue Southbound exit and northbound entrance
San Bruno R19.28 41 North end of SR 35 overlap; northbound exit and southbound entrance
R20.22 42 Crystal Springs Road Southbound exit and northbound entrance; former SR 117
R20.75 43A San Bruno Avenue Signed as exit 43B southbound
R21.02 43B Signed as exit 43A southbound
R21.31 43A Sneath Lane Signed as exit 43B southbound
South San Francisco R22.04 44 Avalon Drive Northbound exit and southbound entrance; former SR 117
R22.62 45 Westborough Boulevard Northbound exit is via exit 44
Daly City R24.20 46 Hickey BoulevardColma, South San Francisco
R24.63 47A Serramonte Boulevard Southbound exit and northbound entrance
R25.28 47B South end of SR 1 overlap; signed as exit 47 northbound
R25.78 48 Eastmoor Avenue, Mission Street Signed as exit 47 northbound
M27.17 49A Daly City, Westlake District (Junipero Serra Boulevard) Signed as exit 49 southbound
M27.17 49B North end of SR 1 overlap; northbound left exit and southbound entrance
San Francisco
SF R0.00-T7.54
R0.74 50 Southbound exit and northbound entrance
R1.77 51 Geneva Avenue, Ocean Avenue
R2.70 52 Monterey Boulevard Southbound exit and northbound entrance
R2.70 52 San Jose Avenue Northbound exit and southbound entrance
R3.28 53 Alemany Boulevard, Mission Street
R4.34 54A Signed as exit 54 southbound
R4.34 54B Northbound exit and southbound entrance
R5.62 55 Cesar Chavez Street, 25th Street
R6.60 56 Mariposa Street, 18th Street
T7.54 57 Sixth Street Northbound exit and southbound entrance
T7.26 King Street Northbound exit and southbound entrance


External links

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