California State Route 237

An aerial view of California State Route 237, Sunnyvale, looking east, taken from above a parking garage on the north side of the road

California State Route 237, San Jose, looking east from above Santa Clara

Route 237 begins at a junction of Grant Road with El Camino Real (SR 82) in Mountain View, as a four lane divided highway. Most traffic comes from California State Route 85. Westbound traffic can connect to Route 85 southbound, but the eastbound traffic connection to Route 85 northbound is labeled as an exit for U.S. 101. Route 237 intersects with Highway 101 at the southern corner of Moffett Field. After this intersection, a carpool lane is added, for a total of three lanes in either direction. It remains like this until the east end of the freeway at Interstate 880, where most eastbound traffic is directed to northbound I-880. The route then becomes a city street (an arterial road), Calaveras Boulevard, in Milpitas, terminating at Interstate 680.

Starting from half a mile after the highway's western terminus, and ending at the I-880 intersection, Route 237 is named the Southbay Freeway. It is mostly constructed to Interstate standards, although there are no current plans to make it an Interstate highway.

Route 237 is known for a number of companies that define Silicon Valley's technological landscape. Many major software and hardware manufacturers have their headquarters along 237. Some of these manufacturers include Lockheed-Martin, Brocade Communications Systems, Nortel Networks, Cisco Systems, Yahoo!, Juniper Networks, TiVo, Ariba and NetApp.

SR 237 is part of the California Freeway and Expressway System,[2] and is part of the National Highway System,[3] a network of highways that are considered essential to the country's economy, defense, and mobility by the Federal Highway Administration.[4]

Before Route 237 was upgraded to freeway status in 1994–1995, it was a four-lane expressway with at-grade intersections, known as Alviso-Milpitas Road or Milpitas-Alviso Road depending on different maps showing the description.

The Route 237 corridor has long been sought as a location for a freeway connector between Interstates 680 and 880. Many possible sites have been suggested, from Montague Expressway in North San Jose to Mission Boulevard in Fremont. One map printed before Route 237's construction to freeway standards between Alviso and 880 showed a new freeway across bay wetlands between Alviso and the Scott Creek Road interchange in South Fremont. Grading and underpasses for a freeway interchange are presently visible along 680 near Scott Creek Road.

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 to an overlap due to a correction or change, and T indicates postmiles classified as temporary (for a full list of prefixes, see California postmile § Official postmile definitions).[9] Segments that remain unconstructed or have been relinquished to local control may be omitted. The entire route is in Santa Clara County.

Location	Postmile [9][1][10]	Exit [11]	Destinations	Notes
Mountain View	R0.00		Grant Road	Continuation beyond SR 82
	R0.00	1A	SR 82 (El Camino Real) – Mountain View, Los Altos	West end of SR 237
	​	West end of freeway
	R0.38	1A	SR 85 north to US 101 north – San Francisco	Eastbound exit and westbound entrance; SR 85 south exit 22A
	R0.38	1B	SR 85 south to SR 82 south – Los Gatos, Santa Cruz	Westbound exit and eastbound entrance; SR 85 north exit 22C
	R0.61	1B	Dana Street	Signed as exit 1C westbound
	M1.55	2	Middlefield Road, Maude Avenue
Sunnyvale	2.48	3A	US 101 south (Bayshore Freeway) – San Jose	Eastbound exit and westbound entrance US 101 north exit 396C
	2.48	3A	US 101 north (Bayshore Freeway) – San Francisco	Westbound exit and eastbound entrance; US 101 south exit 396B
	2.99	3B	Mathilda Avenue to US 101 – San Francisco, Sunnyvale	Former SR 9 south
	​	—	SR 237 Express Lanes	West end of Express Lanes
	R3.97	4	Fair Oaks Avenue	Eastbound exit and westbound entrance
	R4.60	5	Lawrence Expressway (CR G2), Caribbean Drive
Santa Clara	R5.83	6	Great America Parkway
San Jose	6.87	7	North First Street
	8.02	8	Zanker Road
	​	—	SR 237 Express Lanes	Last access point on mainline SR 237
		—	I-880 north – Oakland	Express Lanes access only; eastbound exit and westbound entrance
Milpitas	R9.13	9A	McCarthy Boulevard
	9.34	9	I-880 (Nimitz Freeway) – Oakland, San Jose	Signed as exits 9B (south) and 9C (north); I-880 north exit 8B, south exit 8B-C; former SR 17
	​	East end of freeway
	10.00	10	Main Street	Interchange; exit ramps to Main Street from both directions; former SR 238
	11.08	11	I-680 – Sacramento, San Jose	Interchange; signed as exits 11A (south) and 11B (north); east end of SR 237; I-680 exit 8
	11.08		Calaveras Boulevard	Continuation beyond I-680
1.000 mi = 1.609 km; 1.000 km = 0.621 mi       Electronic toll collection       Incomplete access

•  California Roads portal
•  San Francisco Bay Area portal

Wikimedia Commons has media related to California State Route 237.

• Caltrans: State Route 237 highway conditions
• Caltrans Traffic Conditions Map
• California Highway Patrol Traffic Incidents
• Bay Area FasTrak – includes toll information on the SR 237 Express Lanes and the other Bay Area toll facilities
• California Highways: SR 237
• Highway 237 / I-880 Interchange Reconstruction Project
• California @ AARoads.com - State Route 237