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Oak Knoll District AVA
Oak Knoll District AVA
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Oak Knoll District AVA
Oak Knoll District AVA
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Oak Knoll District AVA
Oak Knoll District AVA

Images Courtesy of Suzanne Becker Bronk

The Oak Knoll District AVA is a Napa Valley Appellation located at the southern end of the mid-valley floor, known for its close proximity to the San Pablo Bay, resulting in relatively cooler and more moderate temperatures.

Appellation Details

Oak Knoll District is located in the southern end of central Napa Valley, California and was officially designated an American Viticultural Area in 2004. Known for its relatively cooler climate and long growing season, the Oak Knoll District is one of Napa Valley's more renowned sub-appellations. Oak Knoll is one of Napa Valley’s flatter appellations and it enjoys primarily deep loam soils. Its location to the north of Napa city places it right in the path of the daily fog that creeps up from the Bay, making it one of the cooler AVAs. Because of this, many white grapes can be found here, along with pockets of Merlot, Cabernet Sauvignon and some old vine Zinfandel.

The center of the appellation is dominated by rich fluvial soils, which are deposited over time by the rivers meandering path and regular flooding. These deep fertile soils make for fruity and charming wines (no strict mountain tannins here!). Things get slightly more complicated in the west, where a small alluvial fan sits at the base of Mount Veeder; here the soil is more gravelly and the terrain slightly undulating. From a climatic perspective, the regular fog keeps the temperatures down, which means the wines tend to be among the more elegant and understated in Napa Valley.


  • Sea level to 800 feet (244 m)
  • The Oak Knoll District of Napa Valley lies at relatively low elevations compared to many other Napa Valley Appellations. This is likely due to the early influence of marine processes and then the development of the Dry Creek Alluvial Fan that was formed as the San Pablo Bay retreated back south over 100,000 years ago.


  • The valley's largest alluvial fan formed by Dry Creek creates the defining feature of the district
  • The northwest area is composed of volcanically derived soils, with stony or gravelly consistency
  • Southern and eastern areas transition from gravel to silty clay loam near the river
  • Irrigation is often essential


  • The Oak Knoll District AVA and neighboring Yountville AVA are two of the coolest of the Napa Valley Sub-Appellations, featuring long, cool growing seasons averaging eight months. The climate in this area is relatively uniform due to the broad, flat nature of the valley floor.
  • Moderate to cool, marine air and fog can remain until late-morning
  • Late afternoon breezes frequently occur, maintaining slightly cooler temperatures than the upper valley.
  • Mid-summer temperatures may reach 92°F (33°C) and drop to around 50°F (10°C) at night.


  • Up to 36 inches (91 cm) annually

Principal Varieties:

  • Cabernet Sauvignon
  • Chardonnay
  • Merlot
  • Sauvignon Blanc
  • Riesling

Oak Knoll District AVA History

Capt. Joseph W. Osborn

Capt. Joseph W. Osborn

The area now known as the Oak Knoll District was originally part of the Rancho Napa land grant, nearly 23,000 acres of land given to Salvador Vallejo in 1838 by Mexican Governor Juan Alvarado. Salvador Vallejo was the younger brother of General Mariano Vallejo and had served as the Captain of Militia at the Sonoma Mission. Rancho Napa bordered George C. Yount's Rancho Caymus to the north and Rancho Yajome to the east, on the other side of the Napa River.

In 1851 Joseph W. Osborne was one of the first people to introduce fine vinifera varieties to the area, including Zinfandel, after purchasing an 800 acre plot of land in Rancho Napa. He named it Oak Knoll Ranch and as early as 1857 was already winning awards in the Bay Area for his wine made from "Foreign Grapes." Despite this early recognition, viticulture was not the most important agricultural activity here during this time, with only around 5% of available land used for vineyards in the 1880's. Then, local wine production declined even further with the onset of Phylloxera in the late 1890's and Prohibition in 1920.

Since the end of Prohibition, numerous vineyards have been planted in the Oak Knoll District, now totalling over 4,150 acres of planted grapevines. The Oak Knoll District was officially designated an American Viticultural Area in 2004.


"The Oak Knoll District is a unique and distinctive grapegrowing area that has been informally recognized as a viticultural area for decades. It deserves to be recognized as an important American Viticultural Area within the Napa Valley."
- Janet Trefethen, Trefethen Vineyards

"The location of the Oak Knoll District at the mouth of the Napa Valley, with our warm sunny days moderated by the daily cool breezes off of the bay, means that the fruit can ripen slowly, maintaining freshness and aromatic lift, while developing a soft and elegant mouthfeel with balance and finesse."
- Steve Matthiasson, Matthiasson Wines

Notable Wines sourced from Oak Knoll District AVA

Alpha Omega
Alpha Omega 2018 'Sunshine Valley Vineyard' Cabernet Sauvignon

Sunshine Valley Vineyard is located on the western side of Highway 29 in the Oak Knoll District AVA.This vineyard is a cooler climate site, facilitating grapes to ripen slowly and allowing aromatics and tannins to ripen harmoniously and evenly at the same natural pace as the Brix. The deep soils provide wonderful complexity and structure.

View Winery Profile

Nickel & Nickel
Nickel & Nickel 2019 'Vaca Vista' Cabernet Sauvignon

Vaca Vista Vineyard sits upon the valley floor in the Oak Knoll District and is our debut Cabernet Sauvignon vineyard in the appellation, set against a scenic backdrop of the Vaca Mountains to the east. The vineyard’s well-drained, gravelly soils and moderate climate provide even ripening, resulting in this structured and polished Cabernet Sauvignon.

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Padis Vineyards
Padis Vineyards 2018 Cabernet Sauvignon

A rich decadent 100% Cabernet Sauvignon from the heart of the Oak Knoll District! Showcases beautiful dark berries on the palate, nice complexity and a luscious long finish!

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Groth Vineyards & Winery
Groth Vineyards & Winery 2019 'Hillview Vineyard' Chardonnay

In 1982, Dennis and Judy Groth acquired their Hillview Esate in the Oak Knoll District of Napa Valley. This single-vineyard Chardonnay comes from a 26-acre block there.

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Oak Knoll District Resources and References

  1. "§ 9.161 Oak Knoll District of Napa Valley" (Title 27: Alcohol, Tobacco and Firearms; Part 9 — American Viticultural Areas; Subpart C — Approved American Viticultural Areas). Code of Federal Regulations. Retrieved October 30, 2007.
  2. Grossinger, R., & Beller, E. (2007). Landscape history of the trancas: Historical ecology research summary for the trancas crossing park and Napa River Trail, city of napa. San Francisco Estuary Institute. Retrieved from https://www.sfei.org/sites/default/files/biblio_files/NapaRiver_LandscapeHist_Trancas.pdf.
  3. Oak Knoll District of Napa Valley. (2018, December 20). Oak Knoll District: Napa Wine, Winery & Grape Growers Association. OAK KNOLL DISTRICT OF NAPA VALLEY. Retrieved September 23, 2022, from https://www.okdnapa.com/
  4. Elliot-Fisk, D.L. 1993. Viticultural Soils of the Trefethen Vineyards, Southern Napa Valley, Napa County, California. 89pp., unpublished.
  5. Oak Knoll District of Napa Valley (n.d.). Retrieved September 23, 2022, from https://www.trefethen.com/learn/place/oak-knoll-district-of-napa-valley/
  6. Palmer, Lyman L.; Wells, Harry Laurenz (1881). History of Napa and Lake Counties, California. Slocum, Bowen & Company. ISBN 978-1363000555.
  7. Weber, Lin (1998). Old Napa Valley: The History to 1900. Wine Ventures Publishing. ISBN 9780966701401.

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