To the west of Napa Valley, between the stretch of the Mayacamas Mountains and the Pacific Ocean, lies the true birthplace of the California wine industry, Sonoma County.

While Russian colonists planted the first vineyards in the region around 1830, vineyard development blossomed during the California Gold Rush of 1849. At that time, a Hungarian entrepreneur named Agoston Haraszthy recognized the business potential of thirsty miners and subsequent settlers and purchased the Mexican-owned vineyards already developed in Sonoma County.

From that time, Haraszthy oversaw vineyard development throughout the area, became the area’s first premium wine producer, and has been recognized as the “Father of the California Wine Industry.”

Notably, many Chinese immigrants who came to the United States to work on the railroad projects during the latter half of the 19th Century also carved out many of the extensive wine caves that the early Sonoma County wine industry demanded. Several are still in use as tasting rooms.

With over 60,000 acres of vineyards throughout 18 recognized American Viticultural Areas (AVAs) or appellations and over 425 wineries, Sonoma County is now one of the world’s most important wine production areas.

Wine Regions of Sonoma County 

Because of the remarkable diversity of soil types, micro-climates, and elevations, Sonoma County growers produce over 60 varieties of grapes for wineries. The AVAs or appellations make up a total land area twice the size of Napa Valley, ranging from coastal, fog-influenced lowlands to sunbaked, west-facing mountainsides.

Here is a brief description, listed alphabetically, of each of the AVAs that produce high-quality grapes for the hundreds of Sonoma County wineries and others: 

Alexander Valley

In northeastern Sonoma County, Alexander Valley vineyards stretch across the valley floor to the base of the Mayacama Mountains. The area boasts diverse ancient soils that primarily produce unique and complex Cabernet Sauvignon varietals.

Bennett Valley

Noted mainly for the excellent Merlot grapes produced here, Bennett Valley is situated in the south-central area of Sonoma County. Vineyards here grow in volcanic, clay soils in a moderately cool climate. The growing season is somewhat longer, allowing the grapes for the wineries in Sonoma to develop more intense, natural flavors. High-quality Syrah, Pinot Noir, and Chardonnay grapes thrive here in one of Sonoma County’s smaller AVAs.


Located in the southernmost part of Sonoma County, Carneros is world-famous for producing the best quality Chardonnay, Pinot Noir, and sparkling wines. Located closest to the San Francisco Bay area, the area enjoys cool fogs and breezes that support the cultivation of cooler climate varietals. This AVA is one of the most popular Sonoma wine tour destinations.

Chalk Hill

A smaller but particularly important AVA, Chalk Hill, lies in Sonoma County’s Russian River Valley in the east-central region of the growing area. The location’s name evolved from the fertile chalky, white ash volcanic soil that produces grapes for excellent white varietals like Chardonnay and Sauvignon Blanc. However, some red varieties are commonly grown here. Vineyards stretch from the valley floor to about 1,600 feet above sea level.

Dry Creek Valley 

In the heart of the north-central sector of Sonoma County, the Dry Creek Valley is sixteen miles long and only two miles wide. Approximately 9,300 acres of vineyards cover this smaller growing region’s valley floor and hillsides. Fifty-eight Sonoma County wineries headquarter here, producing excellent Zinfandels, Bordeaux, and other Mediterranean varietals.

Fort Ross-Seaview

Close to and, in places, a view of the Pacific Ocean, this western portion of Sonoma County has vineyards on hills and ridges that parallel the coastline. They grow on steep, mountainous terrain at elevations between 800 and 1800 feet above sea level. With a cool maritime climate, rugged topography, and marine soils, the yields are low, and managing the vineyards can be difficult. But the quality of the production of Pinot Noir and Chardonnay is excellent.

Fountaingrove District

Home to five Sonoma County wineries and thirty-five vineyards, Fountain Grove AVA produces mostly Cabernet Sauvignon, Merlot, Cabernet Franc, Zinfandel, and Syrah. The area is located in Eastern Sonoma County and is influenced by the high elevation (over 2,000 feet in some places) and the marine influence created by its unique surrounding topography.

Green Valley

One of the smaller appellations in Sonoma County, Green Valley’s climate and soil conditions tend to be the most uniform of the region’s growing areas. At the southwestern corner of the Russian River Valley adjacent to the Sonoma Coast, Green Valley boasts of being the “coolest and foggiest” region. While fog happens to be the trademark for this AVA, nine key Sonoma County wineries and over one hundred growers operate in this area. Pinot Noir is Green Valley’s most popular varietal.

Knights Valley

Considered the most remote appellation, the mountainside vineyards of Knights Valley reside in the northeastern corner of Sonoma County, almost reaching Napa Valley’s Calistoga area. Producing mostly Cabernet Sauvignon grapes along the hillsides and valley floor vineyards, hard-to-reach Knights Valley wineries also produce other Bordeaux varietals as well as Chardonnay, Syrah, and Sauvignon Blanc.

Moon Mountain

Located in the southeast sector of Sonoma Valley, the Moon Mountain AVA includes 1,500 acres of commercial vineyards planted on the western slope of the Mayacamas mountainsides at elevations from 400 to 2,200 feet. Because of the diversity of elevations and microclimates among the meadows, canyons, and ridges, the variety of microclimates and soil types provide the perfect conditions for a wide selection of grape varieties. The Moon Mountain appellation is one of the favorite Sonoma wine tours and wine tasting destinations offered by Platypus Wine Tours of Napa, California.

Petaluma Gap

Petaluma Gap represents the Gateway to Sonoma Valley, just twenty-five miles from the Golden Gate Bridge. With more than eighty vineyards dotting the landscape of hillsides and valleys, the area experiences unique wind and fog conditions created by its proximity to the coast. The region produces excellent Pino Noir, Chardonnay, and Syrah at its nine world-class wineries.

Pine Mountain-Cloverdale Peak

The Pine Mountain-Cloverdale Peak Region makes up the northeastern boundary of Sonoma County. Features include steep topography with mountainous soils as the elevation rises 3,000 feet above the Alexander Valley floor. Many artisan and cult wines are produced here, mainly from Cabernet Sauvignon and other high-elevation red grape varieties.


As one of the smaller AVAs, Rockpile is in the very north-central sector of Sonoma County. This appellation sits west of Lake Sonoma and features intensely flavored grape varieties grown in vineyards situated at around 1,900 feet, where they receive considerable amounts of sunshine.

Russian River Valley

One of the best-known Sonoma County AVAs, Russian River Valley, enjoys cooler than average temperatures resulting from the persistent evening fog from the Pacific that drops the overnight temperature dramatically by as much as 40°F. Grapes produced in the Russian River Valley enjoy a longer growing season and develop fuller and more flavorful maturity than in some other areas. With over 14,000 acres of vineyards, 94 top Sonoma County wineries produce Chardonnay, Pinot Noir, and other popular varietals. Many popular Sonoma wine tours frequent the wineries of the Russian River Valley.

Sonoma Coast

Some of California’s top-rated wines come from the Sonoma Coast AVA grapes. Located near the Pacific Ocean with a cool climate and above-average rainfall, the area stays warm enough to yield mature, fully developed fruit. Sonoma Coast AVA extends nearly the entire length of Sonoma County’s coastline from San Pablo Bay to the border of Mendocino County. The AVA features seven Sonoma County wineries producing a wide selection of varietals, most notably Chardonnay and Pinot Noir.

Sonoma Mountain

The Sonoma Mountain Range, just north of the Carneros AVA, rises to an elevation of about 2,400 feet at the western edge of the Valley of the Moon. The area is unique for its hillside orientation. High-quality Cabernet Sauvignon grapes from around 310 acres of vineyards produce for three local Sonoma County wineries and others.

Sonoma Valley

Situated ideally between the Mayacamas Mountains to the east and the less dominant Sonoma Mountain on the west, Sonoma Valley has long been the hub of Sonoma County’s winemaking history. Protected from the wet, cool influence of the Pacific Ocean, many varieties thrive here and support over 100 excellent wineries in the Valley, many of which are easily accessed and visited by prominent Sonoma wine tours.

West Sonoma Coast

In a far western area of Sonoma County between the steep coastal mountains and the Pacific Ocean, West Sonoma Coast AVA elevations range from 400-to 1800 feet. Twenty-eight wineries thrive here, producing wines with bright acidity and pure flavors.

Explore Sonoma County with Platypus Wine Tours

To experience the fun and variety of world-class Napa Valley and Sonoma County wineries, reserve a safe and memorable wine tour with Platypus Wine Tours of Napa, California. Guests may choose between a scheduled join-in tour or a private, customized individual or group tour.

Learn vineyard insights and winemaking from a knowledgeable Platypus Tour Guide as you tour the vineyards and taste the excellent wines along the way.

For more information and to reserve your place for a join-in or private tour and wine tasting of Napa Valley or Sonoma County wineries, phone 1-707-253-2723. You may also book your Platypus Wine Tour online.