Sonoma County is a leading producer of hops, grapes, prunes, and apples, as well as dairy and poultry products,[8] largely due to the extent of available, fertile agricultural land in addition to the abundance of high-quality water for irrigation.

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.

Spaniards, Russians, and other Europeans claimed and settled in the county from the late 16th to mid-19th century, seeking timber, fur, and farmland.

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 dispute ultimately was between the bigger, richer commercial town of Petaluma and the more centrally located, growing agricultural center of Santa Rosa.

Originally a hunting camp used to obtain game to sell in other markets, by 1854 Petaluma had grown into a bustling center of trade, taking advantage of its position on 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.

[25] 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.

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.

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 becoming sunny, before repeating.

Healdsburg and the City of Sonoma, with similar lows, have even greater diurnal fluctuations due to their significantly warmer highs.

It turns west at Healdsburg, receiving water from Lake Sonoma via Dry Creek, and empties into the Pacific Ocean at Jenner.

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), Hickman's potentilla (Potentilla hickmanii), northern spotted owl (Strix occidentalis caurina), and marbled murrelet (Brachyramphus marmoratus).

Highway 101 links seven of the county's nine incorporated cities: Cloverdale, Healdsburg, Windsor, Santa Rosa, Rohnert Park, Cotati, and Petaluma.

The four-lane freeway section within Santa Rosa, between Fulton Road and Farmers Lane, is called the Luther Burbank Memorial Highway.

[38] 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.

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 United States Office of Management and Budget has designated Sonoma County as the Santa Rosa-Petaluma, CA Metropolitan Statistical Area.

The Supervisors also sit as directors of several local jurisdictions, such as Sonoma Water,[69] and the Agricultural Preservation & Open Space District.

[87][88][89] Agriculture has long played a critical role in Sonoma County's economy, and it makes up a major component of California's Wine Country.

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.

The county is also home to farms producing olives, hay, rye, oats, and various vegetables (particularly tomatoes, carrots, green beans, and celery).

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.

From 1880 until 1988, the only Democrats to carry Sonoma were Winfield Scott Hancock in 1880, Grover Cleveland in 1888 and 1892, Woodrow Wilson in 1912, Franklin D. Roosevelt in 1932 and 1936, and Lyndon B. Johnson in 1964.

Some of the earliest U.S. filmmaking occurred in Sonoma County, including Salomy Jane (1914) and one of Broncho Billy Anderson's 1915 Westerns.