The Oak Knoll District of Napa Valley AVA is an American Viticultural Area

American Viticultural Area

An American Viticultural Area is a designated wine grape-growing region in the United States distinguishable by geographic features, with boundaries defined by the Alcohol and Tobacco Tax and Trade Bureau , United States Department of the Treasury....

 located within Napa Valley AVA

Napa Valley AVA

Napa Valley AVA is an American Viticultural Area located in Napa County, California, United States. Napa Valley is considered one of the top wine regions in the United States...

 at the southern end of valley floor. The appellation

Appellation

An appellation is a legally defined and protected geographical indication used to identify where the grapes for a wine were grown; other types of food often have appellations as well...

's close proximity to San Pablo Bay

San Pablo Bay

San Pablo Bay is a tidal estuary that forms the northern extension of San Francisco Bay in northern California in the United States. Most of the Bay is shallow; however, there is a deep water channel approximately in mid bay, which allows access to Sacramento, Stockton, Benicia, Martinez, and...

 results in a climate that is cooler and more moderate than any region in Napa Valley other than the Los Carneros AVA

Los Carneros AVA

Los Carneros AVA is an American Viticultural Area which includes parts of both Sonoma and Napa counties in California, U.S.A.. It is located north of San Pablo Bay. The proximity to the cool fog and breezes from the bay makes the climate in Los Carneros cooler and more moderate than the wine...

. A wide variety of wine grape

Grape

A grape is a non-climacteric fruit, specifically a berry, that grows on the perennial and deciduous woody vines of the genus Vitis. Grapes can be eaten raw or they can be used for making jam, juice, jelly, vinegar, wine, grape seed extracts, raisins, molasses and grape seed oil. Grapes are also...

s do well in this climate, including varieties not widely grown in other parts of Napa Valley, such as Riesling

Riesling

Riesling is a white grape variety which originated in the Rhine region of Germany. Riesling is an aromatic grape variety displaying flowery, almost perfumed, aromas as well as high acidity. It is used to make dry, semi-sweet, sweet and sparkling white wines. Riesling wines are usually varietally...

 and Pinot Noir

Pinot Noir

Pinot noir is a black wine grape variety of the species Vitis vinifera. The name may also refer to wines created predominantly from Pinot noir grapes...

. Oak Knoll District has begun to develop a reputation for a restrained, delicate style of Chardonnay

Chardonnay

Chardonnay is a green-skinned grape variety used to make white wine. It is originated from the Burgundy wine region of eastern France but is now grown wherever wine is produced, from England to New Zealand...

. The appellation was officially designated a sub-appellation of the Napa Valley AVA on February 25, 2004.