California with 529,000 acres in 2003 of wine grape vineyards is the larger producer of the United States.
In 2003 California produced 417 million gallons which accounted for 67% share of the market: this means that two of every three bottles sold in the U.S.come from this land.The rest of the share are divided into foreign countries, with 26%, and other U.S. countries with 7%. 1294 commercial wineries operate im California providing 207,550 full-time equivalent jobs.
The economic impact of the wine industry on the state, cosidering core businesses and allied industries, is 45.4 billion dollars. All these numbers show perfectly how the wine industry developed in this part of the United States. The grape cultivation started because of the favorable climatic conditions which are very similar to the Mediterranean ones. Probably grapes started to be cultivated in California by Spanish missionaries in the 18th century. Therefore have been the first Italians settlers in the early 1850s which developed a strong red wine-making tradition.Consequently, from the southern missions the vineyards moved towards the northern counties of Sonoma, Napa, and Mendocino where the grape growers found the best climate and soil, very similar to the one left in their country of origin. Today California is traditionally divided into five major wine growing districts, ranged north, south and east of San Francisco and Bay area. The northern coastal region embraces the older wine-growing areas of the Napa, Sonoma and Mendocino counties: Napa Valley, with its excellent wines, is probably the most famous area of California and Sonoma County is California's oldest wine-producing region. In the Central Coast we find Monterey and the Bay Area; east of San Francisco we have Sierra Foothills and Central Valley (Lodi and Woodbridge); then the South Coast with LA and San Diego.

In the whole state are present 89 recognized American Viticultural Areas (A.V.A.):

Alexander Valley
Anderson Valley
Arroyo Grande Valley
Arroyo Seco
Atlas Peak
Ben Lomond
Benmore Valley
California Shenandoah Valley 
Capay Valley
Carmel Valley
Central Coast
Chalk Hill
Chalone
Chiles Valley
Cienega Valley
Clarksburg
Clear Lake
Cole Ranch
Cucamonga Valley
Diablo Grande
Diamond Mountain District
Dry Creek Valley
Dunnigan Hills
Edna Valley
El Dorado
Fair Play
Fiddletown
Guenoc Valley
Hames Valley
Howell Mountain
Knights Valley
Lime Kiln Valley
Livermore Valley
Lodi
Los Carneros
Madera
Malibu-Newton Canyon
McDowell Valley
Mendocino
Mendocino Ridge
Merritt Island
Monterey
Mount Harlan
Mount Veeder
Napa Valley
North Coast
North Yuba
Northern Sonoma
Oakville
Pacheco Pass
Paicines
Paso Robles
Potter Valley
Redwood Valley
River Junction
Rockpile
Russian River Valley
Rutherford
Saint Helena
San Benito
San Francisco Bay
San Lucas
San Pasqual Valley
San Ysidro District
Santa Clara Valley
Santa Cruz Mountains
Santa Lucia Highlands
Santa Maria Valley
Santa Rita Hills
Santa Ynez Valley
Seiad Valley
Sierra Foothills
Solano County Green Valley
Sonoma Coast
Sonoma County Green Valley
Sonoma Mountain
Sonoma Valley
South Coast
Spring Mountain District
Stags Leap District
Suisun Valley
Temecula
Wild Horse Valley
Willow Creek
York Mountain
Yorkville Highlands
Yountville