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Sonoma County, California
County of Sonoma
Sonoma City Hall.jpg
Cannons & Chapel, Fort Ross State Historical Monument, CA 7-5-2010 5-59-11 PM.JPG
Images, from top down, left to right: Bodega Bay, Sonoma Plaza, Fort Ross
Official seal of Sonoma County, California
"Agriculture, Industry, Recreation"
Location in the state of California
Location in the state of California
Country United States
State California
Region San Francisco Bay Area
Incorporated February 18, 1850
Named for the city of Sonoma
County seat (and largest city) Santa Rosa
 • Body Sonoma County Board of Supervisors
 • Total 1,768 sq mi (4,580 km2)
 • Land 1,576 sq mi (4,080 km2)
 • Water 192 sq mi (500 km2)
Highest elevation
4,483 ft (1,366 m)
 • Total 488,863
 • Density 276.51/sq mi (106.760/km2)
Time zone UTC−8 (Pacific Time Zone)
 • Summer (DST) UTC−7 (Pacific Daylight Time)
Area code 707
FIPS code 06-097
GNIS feature ID 1657246

Sonoma County is a county 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. It is to the north of Marin County and the south of Mendocino County. It is west of Napa County and Lake County.

Sonoma County includes the Santa Rosa-Petaluma Metropolitan Statistical Area, which is part of the San Jose-San Francisco-Oakland, CA Combined Statistical Area. It is the northernmost county in the nine-county San Francisco Bay Area region.

In California's Wine Country region, which also includes Napa, Mendocino, and Lake counties, Sonoma County is the largest producer. It has thirteen approved American Viticultural Areas and more than 350 wineries. The voters have twice approved open space initiatives that have provided funding for public acquisition of natural areas, preserving forested areas, coastal habitat, and other open space. More than 8.4 million tourists visit each year, spending more than $1 billion in 2016.

In 2012, Sonoma County ranked as the 22nd county in the United States in agricultural production. By 1920, Sonoma County was ranked as the eighth most agriculturally productive U.S. county and a leading producer of hops, grapes, prunes, apples, as well as dairy and poultry products, largely due to the extent of available, fertile agricultural land in addition to the abundance of high quality water for irrigation. As of 2009, agriculture was largely divided between two nearly monocultural uses: grapes and pasturage.


The Pomo, Coast Miwok and Wappo peoples were the earliest human settlers of Sonoma County, between 8000 and 5000 BC, effectively living within the natural carrying capacity of the land. Archaeological evidence of these First people includes a number of occurrences of rock carvings, especially in southern Sonoma County; these carvings often take the form of Pecked curvilinear nucleated design. Spaniards, Russians, and other Europeans claimed and settled in the county from the late 16th to mid-19th century, seeking timber, fur, and farmland.

The Russians were the first newcomers to establish a permanent foothold in Sonoma County, with the Russian-American Company establishing Fort Ross on the Sonoma Coast in 1812. This settlement and its outlying Russian settlements came to include a population of several hundred Russian and Aleut settlers and a stockaded fort with artillery. However, the Russians abandoned it in 1841 and sold the fort to John Sutter, settler and Mexican land grantee of Sacramento.

Fort Ross was established by the Russians in 1812.

The Mission San Francisco Solano, founded in 1823 as the last and northernmost of 21 California missions, is in the present City of Sonoma, at the northern end of El Camino Real. El Presidio de Sonoma, or Sonoma Barracks (part of Spain's Fourth Military District), was established in 1836 by Comandante General Mariano Guadalupe Vallejo. His duties included keeping an eye on the Russian traders at Fort Ross, secularizing the Mission, maintaining cooperation with the Native Americans of the entire region, and doling out the lands for large estates and ranches. The City of Sonoma was the site of the Bear Flag Revolt in 1846.

Sonoma was one of the original counties formed when California became a state in 1850, with its county seat originally the town of Sonoma. However, by the early 1850s, the town of Sonoma had declined in importance in terms of both commerce and population, its county buildings were crumbling, and it was relatively remote. As a result, elements in the newer, rapidly growing towns of Petaluma, Santa Rosa, and Healdsburg began vying to move the county seat to their towns. The dispute ultimately was between the bigger, richer commercial town of Petaluma and the more centrally located, growing agricultural center of Santa Rosa. The fate was decided following an election for the state legislature in which James Bennett of Santa Rosa defeated Joseph Hooker of Sonoma and introduced a bill that ultimately resulted in Santa Rosa being confirmed as county seat in 1854. Allegedly, several Santa Rosans, not caring to wait, decided to take action and, one night, rode down the Sonoma Valley to Sonoma, took the county seals and records, and brought them to Santa Rosa. Some of the county's land was annexed from Mendocino County between 1850 and 1860.

Early post-1847 settlement and development focused primarily on the city of Sonoma, then the region's sole town and a common transit and resting point in overland travel between the region and Sacramento and the gold fields to the east. However, after 1850, a settlement that soon became the city of Petaluma began to grow naturally near the farthest navigable point inland up the Petaluma River. Originally a hunting camp used to obtain game to sell in other markest, by 1854 Petaluma had grown into a bustling center of trade, taking advantage of its position in the river near a region of highly productive agricultural land that was being settled. Soon, other inland towns, notably Santa Rosa and Healdsburg began to develop similarly due to their locations along riparian areas in prime agricultural flatland. However, their development initially lagged behind Petaluma which, until the arrival of railroads in the 1860s, remained the primary commercial, transit, and break-of-bulk point for people and goods in the region. After the arrival of the San Francisco and North Pacific Railroad in 1870, Santa Rosa began to boom, soon equalling and then surpassing Petaluma as the region's population and commercial center. The railroad bypassed Petaluma for southern connections to ferries of San Francisco Bay.

Six nations have claimed Sonoma County from 1542 to the present:

Flag of New Spain.svg Spanish Empire, 1542, by sea, voyage of Juan Rodríguez Cabrillo as far as the Russian River. Later validated by voyage of Sebastián Vizcaíno, 1602.
Flag of England.svg Kingdom of England, June 1579, voyage of the Golden Hind under Captain Francis Drake at Bodega Bay (exact location disputed).
Flag of Spain (1785-1873 and 1875-1931).svg Spanish Empire, October 1775, the Sonora at Bodega Bay, under Lt. Juan Francisco de la Bodega y Quadra, until 1821, when Mexico gained independence from Spain.
Flag of Russia.svg Russian Empire, by Russian-American Company expedition led by Ivan Alexandrovich Kuskov, the founder of Fort Ross and, from 1812 to 1821, its colonial administrator. Note: There is an overlap of rule with the Mexican Empire (next item), until the Russians sold Fort Ross in 1841 to John Sutter, before leaving the area in 1842.
Flag of Mexico (1821-1823).svg First Mexican Empire, August 1821, under Emperor Agustin Iturbide (October 1822, probable time new flag raised in California), until 1823.
Flag of Mexico (1823-1864, 1867-1893).svg Mexican Republic, 1823 until June 1846.
1stBearFlag.svg California Republic, 14 June 1846 until 9 July 1846.
Flag of the United States.svg United States of America, 9 July 1846 to present.

Sonoma County was severely shaken by the 1906 San Francisco earthquake. The displacements along the faultline averaged 15 feet (4.6 m).


Edward S. Curtis Collection People 100
Pomo girl c. 1924, by Edward S. Curtis' from The North American Indian volume 14.

According to the book California Place Names, "The name of the Indian tribe is mentioned in baptismal records of 1815 as Chucuines o Sonomas, by Chamisso in 1816 as Sonomi, and repeatedly in Mission records of the following years."

According to the Coast Miwok and the Pomo tribes that lived in the region, Sonoma translates as "valley of the moon" or "many moons". Their legends detail this as a land where the moon nestled, hence the names Sonoma Valley and the "Valley of the Moon." This translation was first recorded in an 1850 report by General Mariano Guadalupe Vallejo to the California Legislature. Jack London popularized it in his 1913 novel The Valley of the Moon.

In the native languages there is also a constantly recurring ending tso-noma, from tso, the earth; and noma, village; hence tsonoma, "earth village." Other sources say Sonoma comes from the Patwin tribes west of the Sacramento River, and their Wintu word for "nose". Per California Place Names, "the name is doubtless derived from a Patwin word for 'nose', which Padre Arroyo (Vocabularies, p. 22) gives as sonom (Suisun)." Spaniards may have found an Indian chief with a prominent protuberance and applied the nickname of Chief Nose to the village and the territory. The name may have applied originally to a nose-shaped geographic feature.


Hood Mountain with vineyards in foreground.

According to the U.S. Census Bureau, the county has a total area of 1,768 square miles (4,580 km2), of which 1,576 square miles (4,080 km2) is land and 192 square miles (500 km2) (10.9%) is water.

The county lies in the North Coast Ranges of northwestern California. Its ranges include the Mayacamas and the Sonoma Mountains, the southern peak of the latter being the prominent landform Sears Point. The highest peak in the Mayacamas within the county is Mt. Saint Helena. It has uncommon occurrences of pygmy forest, dominated by Mendocino cypress. The highest peak of the Sonoma Mountains is Sonoma Mountain itself, which boasts two significant public access properties: Jack London State Historic Park and Fairfield Osborn Preserve.

The county includes the City of Sonoma and the Sonoma Valley, in which the City of Sonoma is located. However, these are not synonymous. The City of Sonoma is merely one of several incorporated cities in the county. The Sonoma Valley itself makes up only the southeastern portion of the county, which includes many other valleys and geographic zones. Moreover, the Sonoma Valley itself includes not only the City of Sonoma, but a portion of the City of Santa Rosa and the unincorporated communities of Kenwood, Agua Caliente, Boyes Hot Springs, and Fetters Hot Springs. Other regions of the county beyond the Sonoma Valley include, among others, the Petaluma Valley, the Santa Rosa Plains, the Russian River, the Alexander Valley, and the Dry Creek Valley.

Distinct habitat areas within the county include oak woodland, redwood forest, northern coastal scrub, grassland, marshland, oak savanna and riparian woodland. The California oak woodland in the upper Yulupa Creek and Spring Creek watersheds in Annadel State Park is a relatively undisturbed ecosystem with considerable biodiversity. These forested areas have been characterized as some of the best examples of such woodlands. An unusual characteristic of these forests is the high content of undisturbed prehistoric bunchgrass understory, testifying to the absence of historic grazing or other agriculture.

Trees of the oak woodland habitat include Pacific madrone, Douglas fir, coast live oak, Garry oak and California laurel. Common understory plants are toyon, poison oak, and, at the fringes, coast silk-tassel.


Sonoma County's Dry Creek Valley

Sonoma County, as is often the case with coastal counties in California, has a great degree of climatic variation and numerous, often very different, microclimates. Key determining factors for local climate are proximity to the ocean, elevation, and the presence and elevation of hills or mountains to the east and west. This is in large part due to the fact that, as throughout California, the prevailing weather systems and wind come normally from the Pacific Ocean, blowing in from the west and southwest so that places closer to the ocean and on the windward side of higher elevations tend to receive more rain from autumn through spring and more summer wind and fog. This itself is partly a result of the presence of high and low pressures in inland California, with persistent high summer temperatures in the Central Valley, in particular, leading to low pressures, drawing in moist air from the Pacific, cooling into damp cool breezes and fog over the cold coastal water. Those places further inland and particularly in the lee of significant elevations tend to receive less rain and less, in some cases no, fog in the summer.

The coast itself is typically cool and moist throughout summer, often foggy, with fog generally blowing in during the late afternoon and evening until it clears in the later morning to be sunny, before repeating. Coastal summer highs are typically in the mid to high 60s, warming to the low 70s further from the ocean.

Certain inland areas, including the Petaluma area and the Santa Rosa Plain, are also prone to this normal fog pattern in general. However, they tend to receive the fog later in the evening, the fog tends to be more short-lived, and mid-day temperatures are significantly higher than they are on the coast, typically in the low 80s F. This is particularly true for Petaluma, Cotati and Rohnert Park, and, only slightly less so, Santa Rosa, Windsor, and Sebastopol. In large part this results from lower elevations and the prominent Petaluma Gap in the hills between the ocean to the west and the Petaluma Valley and Santa Rosa Plain to the east.

Areas north of Santa Rosa and Windsor, with larger elevations to the west and further from the fog path, tend to receive less fog and less summer marine influence. Healdsburg to the north of Windsor is less foggy and much warmer, with summer highs typically in the higher 80s to about 90 °F (32 °C). Sonoma and the Sonoma Valley, east of Petaluma, are similar, with highs typically in the very high 70s F to 80 °F (27 °C). This is in part due to the presence of the Sonoma Mountains between Petaluma and Sonoma. Cloverdale far to the north out of the Santa Rosa Plain, is significantly hotter than any other city in the county, with rare evening-morning fog and highs often in the 90s, reaching 100 °F (38 °C) much more frequently than the other cities. Notably, however, the temperature differences among the different areas of the county are greatest for the highs during mid-day, with the diurnal lows much more even throughout the entire county. The lows are closely tied to the evening-morning cooling marine influence, in addition to elevation, bringing similarly cool temperatures to much of region.

These weather patterns contribute to high diurnal temperature fluctuations in much of the county. In summer, daily lows and highs are typically 30-40 °F apart in land, with highs for Petaluma, Cotati, Rohnert Park, Santa Rosa, Windsor, and Sebastopol typically being in the very low 80s F and lows at or near 50 °F (10 °C). Healdsburg and Sonoma, with similar lows, have even greater diurnal fluctuations due to their significantly warmer highs. On the other hand, the coast, with strong marine influence, tends to have low diurnal temperature fluctuation, with summer highs much cooler than the inland towns, typically 65-75 °F, yet lows in the high 40s to low 50s F, fairly comparable to most inland towns.

These microclimates are evident during the rainy seasons as well, with great variation in the amount of rainfall throughout the county. Generally, all of Sonoma County receives a fair amount of rain, with much of the county receiving between about 25 in (640 mm), comparable to areas such as Sonoma and Petaluma, and roughly 30 in (760 mm) normal for Santa Rosa. However, certain areas, particularly in the north-west portion of the county around the Russian River, receive significantly more rainfall. The Guerneville area, for example, typically receives about 50 in (1,300 mm) of rain a year, with annual rain occasionally going as high as 70 in (1,800 mm). Nearby Cazadero typically receives about 72 in (1,800 mm) of rain a year, many times has reached over 100 in (2,500 mm) a year, and sometimes over 120 in (3,000 mm) of rain a year. The Cazadero region is the second wettest place in California after Gasquet.

Snow is exceedingly rare in Sonoma County except in the higher elevations on and around the Mayacamas Mountains, particularly Mount Saint Helena, and Cobb Mountain whose peak is across the line of Lake County.

Ocean, bays, rivers and streams

Russian River mouth on California coast
Goat Rock Beach as viewed from the Jenner Cliffs looking south, showing the mouth of the Russian River at the Pacific Ocean.

Sonoma County is bounded on the west by the Pacific Ocean, and has 76 miles (122 km) of coastline. The major coastal hydrographic features are Bodega Bay, the mouth of the Russian River, and the mouth of the Gualala River, at the border with Mendocino County. All of the county's beaches were listed as the cleanest in the state in 2010.

Six of the county's nine cities, from Healdsburg south through Santa Rosa to Rohnert Park and Cotati, are in the Santa Rosa Plain. The northern Plain drains to the Russian River, or a tributary; the southern Plain drains to the Russian River via the Laguna de Santa Rosa.

Russian River

Much of central and northern Sonoma County is in the watershed of the Russian River and its tributaries. The river rises in the coastal mountains of Mendocino County, north of the city of Ukiah, and flows into Lake Mendocino, a major flood control reservoir. The Russian flows south from the lake through Mendocino to Sonoma County, paralleled by Highway 101. It turns west at Healdsburg, receiving water from Lake Sonoma via Dry Creek, and empties into the Pacific Ocean at Jenner.

Laguna de Santa Rosa

The Laguna de Santa Rosa is the largest tributary of the Russian River. It is 14 miles (23 km) long, running north from Cotati to the Russian River near Forestville. Its flood plain is more than 7,500 acres (30 km2). It drains a 254-square-mile (660 km2) watershed, including most of the Santa Rosa Plain.

The Laguna de Santa Rosa Foundation says:

The Laguna de Santa Rosa is Sonoma County's richest area of wildlife habitat, and the most biologically diverse region of Sonoma County (itself the second-most biologically diverse county in California)... It is a unique ecological system covering more than 30,000 acres (120 km2) and comprised of a mosaic of creeks, open water, perennial marshes, seasonal wetlands, riparian forests, oak woodlands and grasslands... As the receiving water of a watershed where most of the county's human population lives, it is a landscape feature of critical importance to Sonoma County's water quality, flood control, and biodiversity.

The Laguna's largest tributary is Santa Rosa Creek, which runs through Santa Rosa. Its major tributaries are Brush Creek, Mark West Creek, Matanzas Creek, Spring Creek and Piner Creek. Matanzas creek was shown to be polluted in Sonoma county first flush results.

Other water bodies

The boundary with Marin County runs from the mouth of the Estero Americano at Bodega Bay, up Americano Creek, then overland to San Antonio Creek and down the Petaluma River to its mouth at the northwest corner of San Pablo Bay, which adjoins San Francisco Bay. The southern edge of Sonoma County comprises the northern shore of San Pablo Bay between the Marin County border at the Petaluma River and the border with Solano County at Sonoma Creek. Sonoma County has no incorporated communities directly on the shore of San Pablo Bay. At the present there is only a private marina with related facilities called Port Sonoma near the mouth of the Petaluma River. However, the Petaluma River which flows into San Pablo Bay, is navigable up to the city of Petaluma.

The Petaluma River, Tolay Creek, and Sonoma Creek enter the bay at the county's southernmost tip. The intertidal zone where they join the bay is the vast Napa Sonoma Marsh.

Americano Creek, the Petaluma River, Tolay Creek, and Sonoma Creek are the principal streams draining the southern portion of the county. The Sonoma Valley is drained by Sonoma Creek, whose major tributaries are Yulupa Creek, Graham Creek, Calabazas Creek, Schell Creek and Carriger Creek; Arroyo Seco Creek is tributary to Schell Creek.Other creeks include Foss, Felta, and Mill creeks.

Lakes and reservoirs in the county include Lake Sonoma, Tolay Lake, Lake Ilsanjo, Santa Rosa Creek Reservoir, Lake Ralphine, and Fountaingrove Lake.

Marine protected areas of Sonoma County

Like underwater parks, these marine protected areas help conserve ocean wildlife and marine ecosystems.

Threatened/endangered species

A number of endangered plants and animals are found in Sonoma County including the California clapper rail (Rallus longirostris obsoletus), salt marsh harvest mouse (Reithrodontomys raviventris), northern red-legged frog (Rana aurora), Sacramento splittail (Pogonichthys macrolepidotus), California freshwater shrimp (Syncaris pacifica), showy Indian clover (Trifolium amoenum) and Hickman's potentilla (Potentilla hickmanii).

Species of special local concern include the California tiger salamander (Ambystoma californiense) and some endangered plants, including Burke's goldfields (Lasthenia burkei), Sebastopol meadowfoam (Limnanthes vinculans), and Sonoma sunshine or Baker's stickyseed (Blennosperma bakeri).

Endangered species that are endemic to Sonoma County include Sebastopol meadowfoam, Sonoma sunshine, and Pitkin Marsh lily (Lilium pardalinum subsp. pitkinense).

The Sonoma County Water Agency has had a Fisheries Enhancement Program since 1996. Its website says:

"The primary focus of the FEP is to enhance habitat for three salmonids: Steelhead, Chinook salmon, and Coho salmon. These three species are listed as threatened under the U.S. Endangered Species Act. The California Department of Fish and Game considers the Coho salmon endangered."

Adjacent counties

National protected area


Major highways

U.S. Route 101

U.S. Route 101 is the westernmost Federal highway in the U.S.A. Running north/south through the states of California, Oregon, and Washington, it generally parallels the coastline from the Mexico–US border to the Canada–US border. Highway 101 links seven of the county's nine incorporated cities: Cloverdale, Healdsburg, Windsor, Santa Rosa, Rohnert Park, Cotati, and Petaluma. It is a freeway for its entire length within the county.

The four-lane sections of the highway have been heavily congested during peak commute hours for many years and work is being done to widen part of the highway to six lanes. The segment from north of Petaluma (at Old Redwood Highway/Petaluma Boulevard North exit) to Windsor has been fully widened, as has the segment from the Petaluma River bridge to the Marin County border. The two new inner lanes are designated for vehicles with two or more occupants during commute hours. Work is being done around Petaluma to finish the widening within Sonoma County; the widening also involves upgrading the highway to full freeway standards.

State Route 1

Within Sonoma County, Highway 1 follows the coastline from the Mendocino County border, at the mouth of the Gualala River, to the Marin County border, at the Estero Americano (Americano Creek), southeast of Bodega Bay.

State Route 12

CA SR-12 Sonoma
State Route 12 in Sonoma (Broadway)

Highway 12 runs eastward from its intersection with Highway 116 in Sebastopol to Santa Rosa. There it turns south through the Valley of the Moon to Sonoma, then east into Napa County. The four-lane freeway section within Santa Rosa, between Fulton Road and Farmers Lane, is called the Luther Burbank Memorial Highway. That section, especially where it crosses Highway 101, is severely congested during peak commute hours.

The two-lane Bodega Highway runs west from the intersection of Highways 12 and 116 in Sebastopol, through the coastal hills to its intersection with Highway 1, east of Bodega Bay. East of Santa Rosa, Highway 12 is also called Sonoma Highway; and east of the City of Sonoma, Carneros Highway.

State Route 37

Highway 37 connects Highway 101 at Novato, in Marin County, with Interstate 80 in Vallejo, in Solano County, at the top of San Pablo Bay. Within Sonoma County, it is also called Sears Point Road.

State Route 116

Highway 116 is a winding, two-lane rural route that runs from Jenner, at the mouth of the Russian River on the coast, southeast to Arnold Drive near Sonoma. It is also called Guerneville Highway, between Guerneville and Forestville; Gravenstein Highway North, between Forestville and Sebastopol; and Gravenstein Highway South, between Sebastopol and Stony Point Road, west of Rohnert Park. East of Petaluma it is called Lakeville Highway, then Stage Gulch Road.

State Route 121

Highway 121 is a two-lane rural route running from Highway 37 near Sears Point Raceway to Highway 128 in Lake Berryessa, in Napa County.

State Route 128

The northernmost section of Highway 128 is a two-lane, rural route running southeast from Highway 101 at Geyserville, north of Healdsburg, through the Alexander Valley and into Napa County.

Public transportation

  • Sonoma County Transit is the countywide transit operator, providing service to all cities in Sonoma County.
  • CityBus operates within the city limits of Santa Rosa.
  • The cities of Cloverdale and Petaluma also provide their own local bus service.
  • Golden Gate Transit connects Santa Rosa and points south with Marin County and San Francisco.
  • Mendocino Transit Authority runs north from Santa Rosa to Ukiah (via US 101) and to the coast (via California Routes 12 and 1).
  • Sonoma–Marin Area Rail Transit (SMART) is a commuter rail line eventually planned to go between Larkspur in Marin County and Cloverdale in Sonoma County. As of December 2020 the line operates between Larkspur and the Sonoma County Airport.


The Charles M. Schulz - Sonoma County Airport is at 2290 Airport Boulevard, west of Highway 101, between Santa Rosa and Windsor. Its main runway is 5,115 feet (1,559 m) long and 150 feet (46 m) wide, and can accommodate planes up to 95,000 pounds (43,000 kg) maximum gross takeoff weight. It offers fuel, major maintenance, hangar space, and tie-downs for local and transient aircraft. Alaska Airlines, American Airlines, and United Airlines offer regular daily commercial flights.

There are five general aviation airports within the county:

  • Cloverdale Municipal Airport
  • Healdsburg Municipal Airport
  • Petaluma Municipal Airport
  • Sonoma Skypark
  • Sonoma Valley Airport


Railroads of Sonoma County California
Historical railroads of Sonoma County
Mesa Grande train station, about 1910

In 1864, the Petaluma and Haystack Railroad connected the city of Petaluma to a ferry landing at the head of navigation on the Petaluma River.

In 1870, the San Francisco and North Pacific Railroad (SF&NP) connected the City of Santa Rosa to ferry connections at Donahue landing on the Petaluma River. Rail service was extended north to Healdsburg in 1871 and Cloverdale in 1872. In 1884 the railroad was extended south to an alternate ferry connection in Tiburon. This rail line serves as the primary route of Sonoma–Marin Area Rail Transit.

The 3-foot-gauge North Pacific Coast Railroad extended northward in 1876 from a ferry connection at Sausalito through Valley Ford, Freestone, and Occidental to Monte Rio on the lower Russian River. Service was extended to Duncans Mills in 1877 and Cazadero in 1885. The standard gauge Fulton and Guerneville Railroad left the SF&NP at Fulton to reach Korbel in 1876 and Guerneville in 1877. Standard-gauge rails were extended down-river to Duncan Mills in 1909 after the Northwestern Pacific Railroad merger, and narrow-gauge service was discontinued in 1930. The standard-gauge route became River Road after tracks were removed in 1935.

The unique Sonoma Valley Prismoidal Railway linked the city of Sonoma to bay ferries in 1876 and was replaced in 1879 by the 3-foot (0.91 m)-gauge Sonoma Valley Railroad to a ferry landing near the mouth of the Petaluma River. Service was extended from Sonoma to Glen Ellen in 1882. The southern end of the line was extended westward in 1888 to a connection with the SF&NP at Ignacio. This line was converted to standard-gauge in 1890 and remains (in 2018) as Sonoma County's connection to the national rail system at Schellville.

Southern Pacific subsidiary Santa Rosa and Carquinez Railroad extended eastward in 1888 to link Santa Rosa with the national rail system. The portion between Sonoma and Santa Rosa was dismantled in the 1940s after interchange shifted to the former Sonoma Valley line.

A SF&NP branch line from Santa Rosa brought rail service to Sebastopol in 1890. The Petaluma and Santa Rosa Railroad extended interurban service north from a ferry connection in Petaluma to reach Sebastopol in 1904, Santa Rosa in 1905, and Forestville in 1906. Portions of this line were converted to the Joe Rodota Trail after tracks were removed in the 1980s.

The Sonoma–Marin Area Rail Transit commuter rail line inaugurated passenger service on August 25, 2017, utilizing the Northwestern Pacific Railroad right-of-way from Sonoma County Airport station to Larkspur Landing in Marin. The system is planned to extend to Cloverdale Depot.


Historical population
Census Pop.
1850 560
1860 11,867 2,019.1%
1870 19,819 67.0%
1880 25,926 30.8%
1890 32,721 26.2%
1900 38,480 17.6%
1910 48,394 25.8%
1920 52,090 7.6%
1930 62,222 19.5%
1940 69,052 11.0%
1950 103,405 49.7%
1960 147,375 42.5%
1970 204,885 39.0%
1980 299,681 46.3%
1990 388,222 29.5%
2000 458,614 18.1%
2010 483,878 5.5%
2020 488,863 1.0%
U.S. Decennial Census
1790–1960 1900–1990
1990–2000 2010 2020

2020 census

Sonoma County, California - Demographic Profile
(NH = Non-Hispanic)
Race / Ethnicity Pop 2010 Pop 2020 % 2010 % 2020
White alone (NH) 320,027 285,792 66.14% 58.46%
Black or African American alone (NH) 6,769 7,125 1.40% 1.46%
Native American or Alaska Native alone (NH) 3,584 3,053 0.74% 0.62%
Asian alone (NH) 17,777 22,239 3.67% 4.55%
Pacific Islander alone (NH) 1,434 1,708 0.30% 0.35%
Some Other Race alone (NH) 913 2,909 0.19% 0.60%
Mixed Race/Multi-Racial (NH) 12,944 24,599 2.68% 5.03%
Hispanic or Latino (any race) 120,430 141,438 24.89% 28.93%
Total 483,878 488,863 100.00% 100.00%

Note: the US Census treats Hispanic/Latino as an ethnic category. This table excludes Latinos from the racial categories and assigns them to a separate category. Hispanics/Latinos can be of any race.


Places by population, race, and income

2010 Census

The 2010 United States census reported that Sonoma County had a population of 483,878. The racial makeup of Sonoma County was 371,412 (76.8%) White, 7,610 (1.6%) African American, 6,489 (1.3%) Native American, 18,341 (3.8%) Asian, 1,558 (0.3%) Pacific Islander, 56,966 (11.8%) from other races, and 21,502 (4.4%) from two or more races. Hispanic or Latino of any race were 120,430 persons (24.9%).


At the 2000 United States census, there were 458,614 people, 172,403 households, and 112,406 families in Sonoma County. The population density was 291/sq mi (112/km2). There were 183,153 housing units at an average density of 116/sq mi (45/km2).

Of the 172,403 households, 50.3% were married couples living together, 34.8% were non-families, and 10.4% had a female householder with no husband present. 31.9% had children under the age of 18 living with them, 25.7% were individuals, and 10.0% were 65 years of age or older living alone. The average household size was 2.60, and the average family size was 3.12.

The median age was 38 years. 24.5% were under 18, 8.8% from 18 to 24, 29.2% from 25 to 44, 24.9% from 45 to 64, and 12.6% were 65 years of age or older. For every 100 females there were 97 males. For every 100 females age 18 and over, there were 94 males.

The median household income was $53,076, and the median family income was $61,921. Males had a median income of $42,035, females $32,022. The per capita income for the county was $25,724. About 4.7% of families and 8.1% of the population were below the poverty line, including 8.4% of those under age 18 and 5.7% of those age 65 or over.

Metropolitan Statistical Area

The United States Office of Management and Budget has designated Sonoma County as the Santa Rosa, CA Metropolitan Statistical Area. The United States Census Bureau ranked the Santa Rosa, CA Metropolitan Statistical Area as the 105th most populous metropolitan statistical area of the United States as of July 1, 2012.

The Office of Management and Budget has further designated the Santa Rosa, CA Metropolitan Statistical Area as a component of the more extensive San Jose-San Francisco-Oakland, CA Combined Statistical Area, the 5th most populous combined statistical area and primary statistical area of the United States as of July 1, 2012.


City of Santa Rosa, A-26 Invader attack bomber built in 1944.
  • The Pacific Coast Air Museum is located on the southeast corner of the Charles M. Schulz Sonoma County Airport, next to the airplane hangar used in the 1963 Hollywood all-star comedy movie, It's a Mad, Mad, Mad, Mad World.
  • Charles M. Schulz Museum Santa Rosa
  • Sonoma County Museum Santa Rosa
  • Luther Burbank Home and Gardens Santa Rosa
  • Healdsburg Museum & Historical Society Healdsburg
  • Hand Fan Museum of Healdsburg Healdsburg
  • Petaluma Historical Library and Museum Petaluma
  • Wildlife & Natural Science Museum Petaluma
  • Military Antiques & Museum Petaluma
  • Sonoma Valley Museum of Art Sonoma
  • Depot Park Museum Sonoma
  • West County Museum Sebastopol
  • History Museum (aka The Gould-Shaw House Museum) Cloverdale
  • California Indian Museum and Cultural Center Santa Rosa
  • Cotati Museum Cotati

Places of interest

Populated places


Sonoma County has nine incorporated municipalities.

Downtown Santa Rosa
Downtown Santa Rosa, county seat of Sonoma County since 1854
Petaluma CA Street
Downtown Petaluma
Incorporated communities Population Incorporation Date
City of Cloverdale 8,618 February 28, 1872
City of Cotati 7,265 July 16, 1963
City of Healdsburg 11,254 February 20, 1867
City of Petaluma 57,941 April 12, 1858
City of Rohnert Park 40,971 August 28, 1962
City of Santa Rosa 167,815 March 26, 1868
City of Sebastopol 7,379 June 13, 1902
City of Sonoma 10,648 September 3, 1883
Town of Windsor 26,801 July 1, 1992


It also includes the following populated places which are not incorporated:

Census-designated places

Other unincorporated places

Population ranking

The population ranking of the following table is based on the 2010 census of Sonoma County.

county seat

Rank City/Town/etc. Municipal type Population (2010 Census)
1 Santa Rosa City 167,815
2 Petaluma City 57,941
3 Rohnert Park City 40,971
4 Windsor Town 26,801
5 Healdsburg City 11,254
6 Sonoma City 10,648
7 Larkfield-Wikiup CDP 8,884
8 Cloverdale City 8,618
9 Sebastopol City 7,379
10 Cotati City 7,265
11 Boyes Hot Springs CDP 6,656
12 Roseland CDP 6,325
13 Guerneville CDP 4,534
14 Fetters Hot Springs-Agua Caliente CDP 4,144
15 El Verano CDP 4,123
16 Forestville CDP 3,293
17 Penngrove CDP 2,522
18 Graton CDP 1,707
19 Temelec CDP 1,441
20 Sea Ranch CDP 1,305
21 Eldridge CDP 1,233
22 Monte Rio CDP 1,152
23 Occidental CDP 1,115
24 Bodega Bay CDP 1,077
25 Kenwood CDP 1,028
26 Geyserville CDP 862
27 Glen Ellen CDP 784
28 Fulton CDP 541
29 Cazadero CDP 354
30 Bloomfield CDP 345
31 Bodega CDP 220
32 Timber Cove CDP 164
33 Valley Ford CDP 147
34 Jenner CDP 136
35 Sereno del Mar CDP 126
36 Salmon Creek CDP 86
37 Stewarts Point Rancheria AIAN 78
38 Carmet CDP 47

In popular culture

It's a Mad, Mad, Mad, Mad World airplane hangar, next to the Pacific Coast Air Museum, Charles M. Schulz Sonoma County Airport.

Due to the varied scenery in Sonoma County and proximity to the city of San Francisco, a large number of motion pictures have been filmed using venues within the county. Some of the earliest U.S. filmmaking occurred in Sonoma County such as Salomy Jane (1914) and one of Broncho Billy Anderson's 1915 Westerns. Many of these films are classics in American cinematography such as the 1947 film The Farmer's Daughter (starring Joseph Cotten and Loretta Young) and two Alfred Hitchcock films, Shadow of a Doubt of 1943, filmed and set in Santa Rosa and The Birds of 1963, filmed largely in Bodega Bay and Bodega. Many other modern classics have used Sonoma County as a filming venue, including American Graffiti, filmed largely in Petaluma.

A few other representative films produced partially in Sonoma County are:

Sonoma County

  • 1965 The Third Day
  • 1986 Peggy Sue Got Married - Petaluma, including a 1950s makeover of Washington St., the diner "Millie's Chili Bar" (rechristened as "The Donut Hole"), and exterior and interior shots of Santa Rosa High School.
  • 1993 Nowhere to Run - Coleman Valley Road, Occidental, for farmhouse and pond scenes.
  • 2001 The Man Who Wasn't There
  • 2001 Bandits - Flamingo Hotel, Clover milk truck featuring local icon "Clo the cow" and rural county roads.


  • 1955 Many Rivers to Cross - Big Sulphur Creek
  • 1993 So I Married an Axe Murderer - Cloverdale Airport

Glen Ellen

  • 1982 Shoot the Moon - Glen Ellen and Jack London's Wolf House.


  • 1972 American Graffiti
  • 1977 Heroes - Bus stop at corner of Kentucky and C streets. Walnut Street.

Russian River

  • 1925 Braveheart - Along the river.
  • 1942 Holiday Inn - Village Inn Lodge in Monte Rio as the "Holiday Inn" with tons of artificial snow.

Santa Rosa

  • 1963 It's a Mad, Mad, Mad, Mad World - Sequence involving the plane flying full bore, at about 150 knots, through an airplane hangar in less than a second, was shot at the Charles M. Schulz Sonoma County Airport.


  • 1949 Thieves' Highway - Gold Ridge Road.


  • 1988 Tucker: The Man and His Dream.
  • 1996 Scream - Sonoma Community Center on East Napa Street.

The town of Sonoma in southeast Sonoma County hosts the annual Sonoma Valley Film Festival, a nationally recognized event.


Vineyard on northwest flank of Sonoma Mountain.

Agriculture has long played a critical role in Sonoma County's economy, and it makes up a major component of California's Wine Country. Just over 2% of the population works in agriculture, nearly twice the state average. Similar to other regions of the state, the county's mild climate and fertile soil allow for the cultivation of a wide variety of crops, ornamentals, and for the raising of livestock. Beyond the production of grapes, the county's agricultural heartland is primarily located in the west and southwest, and near the cities of Petaluma and Sebastopol. The renowned horticulturalist Luther Burbank, who created hundreds of new varieties of plants and crops, lived and worked in Sonoma County for much of his life.

  • Winemaking— Both the growing of the grapes and their vinting—is an important part of the economic and cultural life of Sonoma County, and by far its most valuable industry. First established in 1850 by a Franciscan priest named Fr. Jose Altimira of the Mission San Francisco Solano, the production of wine has perhaps become Sonoma County's most well known feature. In 2004, growers harvested 165,783 short tons (150,396 t)s) of wine grapes worth US$310 million. In 2006 the Sonoma County grape harvest amounted to over 185,000 tons, exceeding Napa County's harvest by more than 30 percent. About 80 percent of non-pasture agricultural land in the county is for growing wine grapes—58,280.4 acres (235.852 km2) in 2014 of vineyards, with over 1100 growers. In 2019 Sonoma County's wine industry had produced over $654,000,000 worth of wine grapes. The most common varieties planted are Chardonnay, Sauvignon blanc, Cabernet Sauvignon, and Pinot noir, though the area is also known for its Merlot and Zinfandel. Sonoma County is home to more than 425 wineries with sixteen distinct and two shared American Viticultural Areas, including the Sonoma Valley AVA, Russian River Valley AVA, Alexander Valley AVA, Bennett Valley AVA and Dry Creek Valley AVA, the last of which is known for the production of high-quality Zinfandels.
  • Dairy farming- Particularly prominent in the western reaches of the county and in the Petaluma Gap, dairy farming and milk production is another major agricultural sector in Sonoma. Worth nearly $140,000,000 in 2019, Sonoma County is home to nearly 65 registered dairies, including the locally prominent Clover Sonoma and recently the Straus Family Creamery. In addition to milk, the county is home to producers of cheese and yogurt. It was reported that in 2018, just over half of all of the county's dairies were certified as organic.
  • Poultry farming and other livestock- The raising of livestock and poultry can be found throughout the county, but is particularly prominent near the city of Petaluma. The raising of chickens (for eggs and as broilers), cattle, sheep, and to a lesser extent hogs comprised a $250,000,000 industry in 2019.
  • Fishing and Crabbing- Primarily concentrated on Bodega Bay, Sonoma County's fishing industry was worth just over $9,300,000 in 2019. Although numerous species are fished and farmed, the most prominent include Dungeness crab and Chinook salmon.
  • Apples- Behind grapes, apples are the second most common crop grown in Sonoma County, particularly near the city of Sebastopol, and is an industry worth nearly $2,000,000. Although several varieties are grown, the region is most well known for its renowned Gravenstein apples.
  • Other crops- In addition to grapes and apples, Sonoma County is also home to farms producing olives, hay, rye, oats, and various vegetables (particularly tomatoes, carrots, green beans, and celery). There are also numerous nurseries producing flowers and other decorative ornamentals.
  • Timber Industry- Although not as prominent as it once was, Sonoma County does retain a timber industry, particularly along its western and northwestern coastlines. The most common trees that are logged are Redwoods, as well as various Pines and Oaks.

Similar to other Bay Area communities, Sonoma County is also home to several prominent players in the Tech Industry, such as Keysight (formerly a part of Agilent Technologies) in Santa Rosa. Although primarily known for wine, Sonoma County is home to several notable brewing and beverage companies including: Bear Republic Brewing Company, Guayakí, Lagunitas Brewing Company, and the Russian River Brewing Company. The clothing manufacturer Marmot is based in Rohnert Park.


Higher education

  • Empire College, Santa Rosa
  • Golden Gate University (Rohnert Park satellite of Walnut Creek Campus)
  • Santa Rosa Junior College
  • Sonoma State University, Rohnert Park
  • University of San Francisco (Santa Rosa Campus)

The educational system of Sonoma County is similar to that of other counties in California, with a large number of independent districts.

Library system

The Sonoma County Library system offers a central library in downtown Santa Rosa plus 10 branch libraries and two rural stations. More than half of Sonoma County's residents have library cards and borrow more than 2.5 million items per year. The library's website and catalog]receive over 200,000 visits annually. Staff answer nearly half a million reference questions annually for individuals, businesses and government agencies. During a typical school year over 750 classes, more than half the county total, either visit a library or are visited by a children's librarian. The library operates an adult literacy program, and computer terminals are made available for free Internet access.

Images for kids

See also

kids search engine
Sonoma County, California Facts for Kids. Kiddle Encyclopedia.