Sonoma County is a county located in the U.S. state of California. As of the 2020 United States Census, its population was 488,863. Its seat of government and largest city is Santa Rosa.
Santa Rosa is a city in and the county seat of Sonoma County, in the North Bay region of the Bay Area in California. Its population as of the 2020 census was 178,127. It is the largest city in California's Wine Country and Redwood Coast. It is the fifth most populous city in the Bay Area after San Jose, San Francisco, Oakland, and Fremont; and the 25th-most populous city in California.
The Transverse Ranges are a group of mountain ranges of southern California, in the Pacific Coast Ranges physiographic region in North America. The Transverse Ranges begin at the southern end of the California Coast Ranges and lie within Santa Barbara, Ventura, Los Angeles, San Bernardino, Riverside and Kern counties. The Peninsular Ranges lie to the south. The name is due to the ranges' east–west orientation, making them transverse to the general northwest–southeast orientation of most of California's coastal mountains.
Bodega Head is a small promontory on the Pacific coast of northern California in the United States. It is located in Sonoma County at 38.311°N 123.066°W, approximately 40 mi (64 km) northwest of San Francisco and approximately 20 mi (32 km) west of Santa Rosa.
The Hayward Fault Zone is a right-lateral strike-slip geologic fault zone capable of generating destructive earthquakes. The fault was first named in the Lawson Report of the 1906 San Francisco Earthquake in recognition of its involvement in the earthquake of 1868. This fault is about 119 km (74 mi) long, situated mainly along the western base of the hills on the east side of San Francisco Bay. It runs through densely populated areas, including Richmond, El Cerrito, Berkeley, Oakland, San Leandro, Castro Valley, Hayward, Union City, Fremont, and San Jose.
Sonoma Valley is a valley located in southeastern Sonoma County, California, in the North Bay region of the San Francisco Bay Area. Known as the birthplace of the California wine industry, the valley is home to some of the earliest vineyards and wineries in the state, some of which survived the phylloxera epidemic of the 1870s and the impact of prohibition in the early 20th century. Today, the valley's wines are promoted by the U.S. federal government's Sonoma Valley and Carneros AVAs.
The 1857 Fort Tejon earthquake occurred at about 8:20 a.m. on January 9 in central and Southern California. One of the largest recorded earthquakes in the United States, with an estimated moment magnitude of 7.9, it ruptured the southern part of the San Andreas Fault for a length of about 225 miles, between Parkfield and Wrightwood.
The Fairfield Osborn Preserve is a 450-acre nature reserve situated on the northwest flank of Sonoma Mountain in Sonoma County, California. There are eight plant communities within the property, oak woodland being the dominant type. Other communities include chaparral, Douglas fir woodland, native Bunch grass, freshwater marsh, vernal pool, pond and riparian woodland. The flora is extremely diverse including many native trees, shrubs, wildflowers, grasses, lichens and mosses. A diverse fauna inhabits this area including black-tailed deer, coyote, bobcat and an occasional mountain lion; moreover, there are abundant avifauna, amphibians, reptiles and insects.
Bennett Valley is a northwest- to southeast-trending valley in Sonoma County, California, US, approximately 1 mile (1.6 km) wide in its northwestern portion, where the southeast extremity of Santa Rosa, California is located. The axis of the valley floor slopes 40 feet (12 m) per mile from the pinched central portion of the valley, where knolls divide the northwestern from the southeastern segment of the valley. Bennett Valley is drained by Matanzas Creek which is incised into the valley floor; an unnamed stream and Spring Creek drain into Matanzas Creek from the east side of Bennett Valley below the Matanzas Creek Reservoir. A flood-control reservoir on Matanzas Creek in the central portion of the valley collects water from the drainage of the upper portion of the valley. Precipitation in the valley varies from approximately 35 to 40 inches per year. The latter amount falls on Taylor Mountain, located immediately above Bennett Valley, in an outlier spur of the Sonoma Mountains sometimes called the Los Gullicos Range. Rainfall occurs primarily during winters, separated by warm dry summers. Bennett Valley is accessed chiefly via Bennett Valley Road, which traverses the valley floor to connect southeast Santa Rosa with Warm Springs Road in Glen Ellen.
Piner Creek is a stream in northeast Santa Rosa, California, United States which originates as an outlet of Fountaingrove Lake. Piner Creek discharges to Santa Rosa Creek which in turn joins the Laguna de Santa Rosa. The upper reaches in the foothills of the Mayacamas Mountains are at elevations of 200 to 300 feet, while the lower and middle reaches are located on the Santa Rosa Plain at elevations of between the 110- and 140-foot contours; therefore, these lower reaches have a gradient of about 1:250 toward the southwest. Geologic studies in the lower and middle reaches of Piner Creek indicate groundwater levels ranging from three to 15 feet below the surface. Prior to extensive urban development of the middle and lower reaches, the landscape earlier bore extensive agricultural uses including plum orchards, which fruit was subsequently processed for prunes.
The Geysers is the world's largest geothermal field, containing a complex of 18 geothermal power plants, drawing steam from more than 350 wells, located in the Mayacamas Mountains approximately 72 miles (116 km) north of San Francisco, California.
Five Creek is a westward flowing stream that rises in the city of Rohnert Park, California, United States and discharges to the Laguna de Santa Rosa. The creek is channelized as it flows through the city and runs in an artificially rectilinear fashion. Considered waters of the United States as a jurisdictional matter, Five Creek has potential habitat for the California red-legged frog and the Western pond turtle.
The Bennett Valley AVA is an American Viticultural Area located in Sonoma County, California. The boundaries of this appellation lie completely within the North Coast AVA, almost completely within the Sonoma Valley AVA and overlaps into some areas of the Sonoma Coast AVA and Sonoma Mountain AVA. The region was granted AVA status on December 23, 2003 following the petition of Matanzas Creek Winery. The AVA is surrounded to the south, east and west by the Sonoma Mountains and to the north by the city of Santa Rosa, California. The region receives a moderating effect on its climate from Pacific Ocean through the cool coastal fogs and breeze that creep into the area from the southwest through Crane Canyon between Sonoma Mountain and Taylor Mountain. Barbera, Cabernet Sauvignon, Cabernet Franc, Chardonnay, Grenache, Merlot, Pinot noir, Sauvignon blanc and Syrah are the leading grape varieties planted.
The Dry Creek Valley AVA is an American Viticultural Area in Sonoma County, California, located northwest of the town of Healdsburg. The valley is formed by Dry Creek, a tributary of the Russian River, and is approximately 16 miles (25.7 km) long and 2 miles (3.2 km) wide. The appellation benefits from the proximity of the Lake Sonoma reservoir for irrigation in this relatively dry area.
At 04:56 and 06:19 UTC on October 2, 1969, a pair of earthquakes of magnitude 5.6 and 5.7, respectively, struck the city of Santa Rosa, California, killing one person and damaging buildings. The maximum felt intensity for the two events was VII and VIII (Severe) respectively on the Mercalli intensity scale. The $8.35 million cost of the earthquakes went mostly to replace buildings damaged beyond repair. There were at least 200 aftershocks after the initial pair of earthquakes. At the time they were the largest earthquakes to affect the northern San Francisco Bay Area since the 1906 San Francisco earthquake.
Sonoma Water, formerly known as the Sonoma County Water Agency, maintains a water transmission system that provides naturally filtered Russian River water to more than 600,000 residents in portions of Sonoma County, California and Marin County, California. The Water Agency is a water wholesaler that sells potable water to nine cities and special districts that in turn sell drinking water to their residents. These cities and special districts are: the City of Santa Rosa, Rohnert Park, Cotati, Petaluma, Sonoma, the Town of Windsor, Valley of the Moon Water District, Marin Municipal Water District, and North Marin Water District.
The Sonoma County Library is a medium-sized public library system that serves the nine cities and unincorporated areas of Sonoma County, California. The library system is a joint powers authority, with administration located at the Administrative Offices, 6135 State Farm Dr, Rohnert Park, CA 94928.
The 2014 South Napa earthquake occurred in the North San Francisco Bay Area on August 24 at . At 6.0 on the moment magnitude scale and with a maximum Mercalli intensity of VIII (Severe), the event was the largest in the San Francisco Bay Area since the 1989 Loma Prieta earthquake. The epicenter of the earthquake was located to the south of Napa and to the northwest of American Canyon on the West Napa Fault.
The 1979 Coyote Lake earthquake occurred at on August 6 with a moment magnitude of 5.7 and a maximum Mercalli Intensity of VII. The shock occurred on the Calaveras Fault near Coyote Lake in Santa Clara County, California and resulted in a number of injuries, including some that required hospitalization. Most of the $500,000 in damage that was caused was non-structural, but several businesses were closed for repairs. Data from numerous strong motion instruments was used to determine the type, depth, and extent of slip. A non-destructive aftershock sequence that lasted throughout the remainder of the month was of interest to seismologists, especially with regard to fault creep, and following the event local governments evaluated their response to the incident.
The 1898 Mare Island earthquake occurred in Northern California on with a moment magnitude of 5.8–6.4 and a maximum Mercalli intensity of VIII–IX (Severe–Violent). Its area of perceptibility included much of northern and central California and western Nevada. Damage amounted to $350,000 and was most pronounced on Mare Island, a peninsula in northern San Francisco Bay. While relatively strong effects there were attributed to vulnerable buildings, moderate effects elsewhere in the San Francisco Bay Area consisted of damaged or partially collapsed structures, and there were media reports of a small tsunami and mostly mild aftershocks that followed.
