State Route 12 (SR 12) is a

state highway A state highway, state road, or state route (and the equivalent provincial highway, provincial road, or provincial route) is usually a road that is either ''numbered'' or ''maintained'' by a sub-national state or province. A road numbered by a ...

in the

U.S. state In the United States, a state is a constituent political entity, of which there are 50. Bound together in a political union, each state holds governmental jurisdiction over a separate and defined geographic territory where it shares its sover ...

California California is a U.S. state, state in the Western United States, located along the West Coast of the United States, Pacific Coast. With nearly 39.2million residents across a total area of approximately , it is the List of states and territori ...

that travels in an east–west direction from State Route 116 in

Sebastopol Sevastopol (; uk, Севасто́поль, Sevastópolʹ, ; gkm, Σεβαστούπολις, Sevastoúpolis, ; crh, Акъя́р, Aqyár, ), sometimes written Sebastopol, is the largest city in Crimea, and a major port on the Black Sea ...

Sonoma County Sonoma County () is a county (United States), county located in the U.S. state of California. As of the 2020 United States Census, its population was 488,863. Its county seat and largest city is Santa Rosa, California, Santa Rosa. It is to the n ...

to State Route 49 just north of San Andreas in

Calaveras County Calaveras County (), officially the County of Calaveras, is a county in both the Gold Country and High Sierra regions of the U.S. state of California. As of the 2010 census, the population was 45,292. The county seat is San Andreas. Angels Ca ...

. The route connects the Sonoma and Napa valleys with the

Sacramento–San Joaquin River Delta The Sacramento–San Joaquin River Delta, or California Delta, is an expansive inland river delta and estuary in Northern California. The Delta is formed at the western edge of the Central Valley by the confluence of the Sacramento and San ...

and the

Sierra Foothills The Sierra Foothills AVA (established in 1987) is an American Viticultural Area in the foothills of the Sierra Nevada in the U.S. state of California in the United States. Wine grapes were introduced to the area in the nineteenth century during the ...

. It is constructed to freeway standards from the Fulton Road/South Wright Road stoplight in

Santa Rosa Santa Rosa is the Italian, Portuguese and Spanish name for Saint Rose. Santa Rosa may also refer to: Places Argentina *Santa Rosa, Mendoza, a city * Santa Rosa, Tinogasta, Catamarca * Santa Rosa, Valle Viejo, Catamarca *Santa Rosa, La Pampa * Sa ...

, to its partial interchange with Farmers Lane (also in Santa Rosa).

Route description

There are six segments that are overlaps with other highways: in the Napa and Sonoma valleys with SR 121, in the southern Napa Valley with SR 29, a short overlap with I-80 at Cordelia Junction in Fairfield, another short overlap with SR 99 in Lodi, and overlaps with SR 88 and SR 26 in the Sierra foothills. The highway is mainly two lane rural highway, with the exception of short segments in Santa Rosa and Fairfield/Suisun City, the overlaps with I-80 and SR 99, and segments within developed areas, such as Santa Rosa and Lodi.California State Automobile Association map San Francisco Bay, 1-09 edition SR 12 begins in the west at its junction with SR 116 in

. After passing east through Santa Rosa on a mix of freeway, surface street, and expressway, it turns south into the Sonoma Valley, passing the

Jack London State Historic Park Jack London State Historic Park, also known as Jack London Home and Ranch, is a California State Historic Park near Glen Ellen, California, United States, situated on the eastern slope of Sonoma Mountain. It includes the ruins of a house burned ...

Glen Ellen Glen Ellen is a census-designated place (CDP) in Sonoma Valley, Sonoma County, California, United States. The population was 784 at the 2010 census, down from 992 at the 2000 census. Glen Ellen is the location of Jack London State Historic Par ...

. It winds through Sonoma on surface streets, where the historic

Vallejo Estate The Vallejo Estate is a historic house in Sonoma, California, one of the six sites that comprises the Sonoma State Historic Park. The estate was owned by General Mariano Guadalupe Vallejo, a ''Californio'' military leader and landowner. Vallejo ...

and Sonoma Mission, both part of the

Sonoma State Historic Park Sonoma State Historic Park is a California State Park located in the center of Sonoma, California. The park consists of six sites: the Mission San Francisco Solano, the Sonoma Barracks (sometimes called the Presidio of Sonoma), the Blue Wing I ...

, are. South of Sonoma, SR 12 turns east, joining SR 121 for nearly nine miles, then turns south briefly as it leaves SR 121 and joins the four-lane expressway SR 29 to cross the

Napa River The Napa River is a river approximately long in the U.S. state of California. It drains a famous wine-growing region called the Napa Valley, in the mountains north of the San Francisco Bay. Milliken Creek and Mt. Veeder watersheds are a few of ...

. Four miles after joining SR 29 it splits off towards the east on Jameson Canyon Road; this section is also the 1928 re-alignment of the

Lincoln Highway The Lincoln Highway is the first transcontinental highway in the United States and one of the first highways designed expressly for automobiles. Conceived in 1912 by Indiana entrepreneur Carl G. Fisher, and formally dedicated October 31, 1913 ...

, the first road across America. After a brief merge with Interstate 80, SR 12 branches off to the east as an expressway through Fairfield and

Suisun City Suisun City ( ; Wintun for "where the west wind blows") is a city in Solano County, California, United States. The population was 29,518 at the 2020 census. The city takes its name from the adjacent Suisun Bay, which in turn is named for the Su ...

. East of Suisun it becomes two lanes again and crosses south of

Travis Air Force Base Travis Air Force Base is a United States Air Force base under the operational control of the Air Mobility Command (AMC), located three miles (5 km) east of the central business district of the city of Fairfield, in Solano County, Californi ...

, through rolling fields with numerous wind turbines. Just past Braid's Bridge is the

Western Railway Museum The Western Railway Museum, in Solano County, California is located on Highway 12 between Rio Vista and Suisun. The museum is built along the former mainline of the Sacramento Northern Railway. Their collection focuses on trolleys, as it is ...

. At Rio Vista, SR 12 crosses the Helen Madere Memorial Bridge over the

Sacramento River The Sacramento River ( es, Río Sacramento) is the principal river of Northern California in the United States and is the largest river in California. Rising in the Klamath Mountains, the river flows south for before reaching the Sacramento–S ...

, entering the

California Delta California is a state in the Western United States, located along the Pacific Coast. With nearly 39.2million residents across a total area of approximately , it is the most populous U.S. state and the 3rd largest by area. It is also the m ...

. This stretch of the river has twice been the site of much-publicized inland excursions by humpback whales, presumably veering off course while making their annual migrations along the Pacific coast. In 1985

Humphrey the whale Humphrey the Whale is a humpback whale that twice deviated from his Mexico to Alaska migration by entering San Francisco Bay. This behavior is unusual for a humpback whale, and Humphrey attracted wide media attention when entering the bay in bo ...

swam about as far as the Rio Vista Bridge. In 2007 a humpback mother and calf dubbed Delta and Dawn circled for several days just upstream of the bridge, seemingly reluctant to pass under it again after having spent the previous three or four weeks upriver near

Sacramento ) , image_map = Sacramento County California Incorporated and Unincorporated areas Sacramento Highlighted.svg , mapsize = 250x200px , map_caption = Location within Sacramento ...

. From the Sacramento River to the junction with Interstate 5, SR 12 crosses several of the waterways of the California Delta and the low-lying fields between them. Through Lodi it becomes a wide four-lane business route. After another brief merger with another freeway, this time SR 99, SR 12 heads east into the Sierra foothills (with shared segments with SR 88 and SR 26) before ending at the junction with SR 49 just north of San Andreas. SR 12 is part of the

California Freeway and Expressway System The California Freeway and Expressway System is a system of existing or planned freeways and expressways in the U.S. state of California. It encompasses both State highways and federal highways in California. It is defined by Article 2 (commenci ...

, and in Sebastopol, from US 101 to Sonoma, and from I-80 to SR 88 is 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 The Federal Highway Administration (FHWA) is a division of the United States Department of Transportation that specializes in highway transportation. The agency's major activities are grouped into two programs, the Federal-aid Highway Program a ...

. SR 12 is eligible to be included in the State Scenic Highway System; however, it is only designated as a scenic highway from its intersection with Danielli Avenue east of

to its junction with London Way near Agua Caliente, meaning that it is a substantial section of highway passing through a "memorable landscape" with no "visual intrusions", where the potential designation has gained popular favor with the community. SR 12 has been designated by various state laws and through local usage as the Valley of the Moon Scenic Route (the portion running through Sonoma County, though the first sign with this name is at the intersection of Farmers Lane and Fourth Street in Santa Rosa); Luther Burbank Memorial Highway from Santa Rosa to Sebastopol (after botanist

Luther Burbank Luther Burbank (March 7, 1849 – April 11, 1926) was an American botanist, horticulturist and pioneer in agricultural science. He developed more than 800 strains and varieties of plants over his 55-year career. Burbank's varied creations incl ...

). SR 12 is also known as Sonoma Highway between Santa Rosa and the west side of the city of Sonoma; Broadway between

Sonoma Plaza Sonoma Plaza (Spanish: ''Plaza de Sonoma'') is the central plaza of Sonoma, California. The plaza, the largest in California, was laid out in 1835 by Mariano Guadalupe Vallejo, founder of Sonoma. Description This plaza is surrounded by many his ...

and its junction with SR 121 in Schellville; Carneros Highway for the length of its

concurrency Concurrent means happening at the same time. Concurrency, concurrent, or concurrence may refer to: Law * Concurrence, in jurisprudence, the need to prove both ''actus reus'' and ''mens rea'' * Concurring opinion (also called a "concurrence"), a ...

with 121 between Schellville and its junction and the north end of its concurrency with SR 29 near Napa; Jameson Canyon Road from where its concurrency with SR 29 ends in

American Canyon American Canyon (previously known as Napa Junction) is a city located in southern Napa County, California, northeast of San Francisco, part of the San Francisco Bay Area. The 2020 census reported the city's population as 21,837. Its ZIP Code i ...

to its junction with

I-80 Interstate 80 (I-80) is an east–west transcontinental freeway that crosses the United States from downtown San Francisco, California, to Teaneck, New Jersey, in the New York metropolitan area. The highway was designated in 1956 as one o ...

Cordelia Cordelia is a feminine given name. It was borne by the tragic heroine of Shakespeare's ''King Lear'' (1606), a character based on the legendary queen Cordelia. The name is of uncertain origin. It is popularly associated with Latin '' cor'' ( geni ...

; and Rio Vista Highway from I-80 to SR 160 east of Rio Vista, and informally as "Blood Alley" from Lodi to Fairfield. The segment through Lodi to the overlap with SR 99 is on Kettleman Lane.California State Automobile Association map Gold Country, 7-05 edition

History

Before the 1964 renumbering, this route was signed as Sign Route 12 for most of its length. However, SR 12 was designated as Legislative Route 51 (LR 51) from SR 116 to SR 121 before the 1964 renumbering. Portions of the route from SR 29 to I-80 ran concurrently with State Route 29 or with State Route 37; this was also LR 8 and a former routing of

US 40 U.S. Route 40 or U.S. Highway 40 (US 40), also known as the Main Street of America, is a major east–west United States Highway traveling across the United States from the Mountain States to the Mid-Atlantic States. As with most routes wh ...

. The portion from I-80 to then-

US 99 U.S. Route 99 (US 99) was a main north–south United States Numbered Highway on the West Coast of the United States until 1964, running from Calexico, California, on the US–Mexico border to Blaine, Washington, on the U.S.-Canada borde ...

was designated as LR 53 in 1919; from US 99 to SR 49, it was designated as LR 24. In 1976, the discontinuity resulting from the concurrency with State Route 84 was removed.

Future extension

Plans call for a western extension of its western terminus to State Route 1 near

Bodega Bay Bodega Bay ( es, Bahía Bodega) is a shallow, rocky inlet of the Pacific Ocean on the coast of northern California in the United States. It is approximately across and is located approximately northwest of San Francisco and west of Santa Ros ...

.Democrat: County OKs bypass around Forestville
, accessed June 15, 2010 Plans also called for Route 12 to be built as a freeway from Farmers Lane to Melita Road, in Santa Rosa; however, as of 2014, this project was delayed due to community opposition.

Major intersections

References

External links

California @ AARoads.com – State Route 12Caltrans: Route 12 highway conditions
{{Commons category, California State Route 12

012 012 may refer to: * Tyrrell 012, a Formula One racing car * The dialing code for Pretoria Pretoria () is South Africa's administrative capital, serving as the seat of the executive branch of government, and as the host to all foreign embassie ...

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