California State Route 61
|Defined by Streets and Highways Code § 361, 412, and 560|
|Maintained by Caltrans|
|Length||6.970 mi (11.217 km)|
Length of SR 112 is 1.782 mi (3 km) and length of SR 260 is 1.924 mi (3 km)
|Restrictions||No hazardous materials in the Posey and Webster Street tubes|
|South end||SR 185 in San Leandro|
|I-880 in San Leandro|
|North end||I-880 in Oakland|
State Route 61 (SR 61) is a state highway in the U.S. state of California, running along the eastern edge of Oakland International Airport and through Alameda. Two additional "hidden" state highways, State Route 112 (SR 112) and State Route 260 (SR 260), are also signed as part of SR 61, despite having legal descriptions separate from Route 61.
SR 112 runs along Davis Street from State Route 185 (East 14th Street) west to Doolittle Drive in San Leandro. SR 61 proper then follows Doolittle Drive north near the eastern boundary of Oakland International Airport to Bay Farm Island and across the Bay Farm Island Bridge to Alameda Island. SR 61 then runs on various city streets in Alameda to Webster Street. SR 260 then goes from Webster Street through the Posey and Webster Street tubes to near Interstate 880 in Oakland. SR 112 has been signed going eastbound as early as 2012 
As legislatively defined, Route 61 extends as far north as Albany and as far south as the Dumbarton Bridge's east approach. Only the portion between Routes 260 and 112 is constructed; the unbuilt remainder of the route exists today either as open San Francisco Bay or wetlands. This route would likely have sat atop landfill; as public opinion shifted against filling in the bay, completing the remaining portions of Route 61 also fell out of favor. Route 87 is another highway once proposed to traverse present-day wetlands and open water.
The combined SR 112/61/260 route begins at SR 185 in San Leandro. Running along Davis Street, it then interchanges with Interstate 880 before it heads to Doolittle Drive. It then continues northward along Doolittle Drive and enters the city of Oakland, running along the eastern boundary of Oakland International Airport. The route then enters the city of Alameda at Bay Farm Island before crossing the San Leandro Bay via a drawbridge to Alameda Island. SR 61 then goes west along Otis Drive, then north along Broadway until reaching Encinal Avenue. The highway then heads west on Encinal Avenue and Central Avenue to Webster Street. The route then runs across Webster Street and through the Posey and Webster Street tubes before terminating at I-880 and 7th Street in Oakland. The highway does not directly intersect with I-880 here, so drivers are instructed to use the freeway's off-ramps at Broadway, the southbound on-ramp at Oak Street, or the northbound on-ramp at Jackson Street.
California's legislature has relinquished state control of the segment along Webster Street between Central Avenue and Atlantic Avenue, and thus that portion is now maintained by the City of Alameda.
SR 61 is part of the California Freeway and Expressway System, and all three routes are part of the National Highway System, a network of highways that are considered essential to the country's economy, defense, and mobility by the Federal Highway Administration.
Except where prefixed with a letter, postmiles were measured on the road as it was in 1964, based on the alignment that existed at the time, and do not necessarily reflect current mileage. R reflects a realignment in the route since then, M indicates a second realignment, L refers an overlap due to a correction or change, and T indicates postmiles classified as temporary ( ). Segments that remain unconstructed or have been relinquished to local control may be omitted. The entire route is in Alameda County.
|San Leandro||1.78[N 1]||Callan Avenue||Continuation beyond SR 185|
|1.78[N 1]||SR 185 (East 14th Street)||South end of SR 61; east end of unsigned SR 112|
|0.60[N 1]||I-880 (Nimitz Freeway) – Oakland, San Jose||Interchange|
|Davis Street, Doolittle Drive||West end of unsigned SR 112|
|Oakland||16.07||98th Avenue to I-880 – Oakland International Airport||Interchange|
|Alameda||18.55||Bay Farm Island Bridge over San Leandro Bay|
|Central Avenue, Webster Street||North end of state maintenance|
|||Atlantic Avenue, Ralph Appezzato Memorial Parkway||South end of unsigned SR 260 and state maintenance|
|R0.86[N 2]||Wilver "Willie" Stargell Avenue||At-grade intersection; former southbound exit and entrance interchange; formerly Mariner Square Drive|
|R0.86[N 2]||Constitution Way, Marina Village Parkway||Interchange; southbound left exit and northbound entrance|
|Alameda–Oakland line||R1.12[N 2]|
|Posey and Webster Street Tubes under Oakland Estuary|
|Oakland||R1.92[N 2]||7th Street to I-880 (Nimitz Freeway) / I-980 east – San Francisco, San Jose, Jack London Square||North end of SR 61 and unsigned SR 260|
|R1.92[N 2]||Harrison Street||Continuation beyond 7th Street|
|1.000 mi = 1.609 km; 1.000 km = 0.621 mi|
- Indicates that the postmile represents the distance along SR 112 rather than SR 61.
- Indicates that the postmile represents the distance along SR 260 rather than SR 61.
- California Department of Transportation. "State Truck Route List". Sacramento: California Department of Transportation. Archived from the original (XLS file) on June 30, 2015. Retrieved June 30, 2015.
- California Highways: State Route 61
- "Special Route Restrictions". Caltrans. Retrieved 2014-07-26.
- "Signage for SR 112 east". Retrieved April 3, 2021.
- "CA Codes (shc:300-635)". Leginfo.ca.gov. Archived from the original on 2014-10-06. Retrieved 2013-10-19.
- "Article 2 of Chapter 2 of Division 1". California Streets and Highways Code. Sacramento: California Office of Legislative Counsel. Retrieved February 6, 2019.
- Federal Highway Administration (March 25, 2015). National Highway System: San Francisco, CA (PDF) (Map). Scale not given. Washington, DC: Federal Highway Administration. Retrieved October 14, 2017.
- Natzke, Stefan; Neathery, Mike & Adderly, Kevin (June 20, 2012). "What is the National Highway System?". National Highway System. Washington, DC: Federal Highway Administration. Retrieved July 1, 2012.
- California Department of Transportation (April 2008). "Log of Bridges on State Highways". Sacramento: California Department of Transportation.
- California Department of Transportation, All Traffic Volumes on CSHS, 2007
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