Napa County wine is wine

Wine

Wine is an alcoholic beverage, made of fermented fruit juice, usually from grapes. The natural chemical balance of grapes lets them ferment without the addition of sugars, acids, enzymes, or other nutrients. Grape wine is produced by fermenting crushed grapes using various types of yeast. Yeast...

 made in Napa County

Napa County, California

Napa County is a county located north of the San Francisco Bay Area in the U.S. state of California. It is coterminous with the Napa, California, Metropolitan Statistical Area. As of 2010 the population is 136,484. The county seat is Napa....

, California

California

California is a state located on the West Coast of the United States. It is by far the most populous U.S. state, and the third-largest by land area...

, USA. County

County (United States)

In the United States, a county is a geographic subdivision of a state , usually assigned some governmental authority. The term "county" is used in 48 of the 50 states; Louisiana is divided into parishes and Alaska into boroughs. Parishes and boroughs are called "county-equivalents" by the U.S...

 names in the United States automatically qualify as legal 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 of origin for wine produced from grapes grown in that county and do not require registration with the United States Department of the Treasury

United States Department of the Treasury

The Department of the Treasury is an executive department and the treasury of the United States federal government. It was established by an Act of Congress in 1789 to manage government revenue...

 Alcohol and Tobacco Tax and Trade Bureau

Alcohol and Tobacco Tax and Trade Bureau

The Alcohol and Tobacco Tax and Trade Bureau, statutorily named the Tax and Trade Bureau and frequently shortened to TTB, is a bureau of the United States Department of the Treasury....

.
The vast majority of Napa County is covered by the boundaries of the world-famous 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...

, 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....

, and its various sub-appellations. The portion of the county that falls outside of the boundaries of the Napa Valley AVA is northeast of the Chiles Valley AVA

Chiles Valley AVA

The Chiles Valley AVA is an American Viticultural Area located within Napa Valley AVA. The Chiles Valley is nestled in the Vaca Mountains on the northeast side of Napa Valley. The appellation has a warmer and more continental climate than other portions of Napa Valley...

, where few grapes are cultivated.

Few wines are produced that carry a Napa County appellation of origin designation, as almost every wine produced from grapes grown in the county is eligible for release with the more commercially profitable Napa Valley AVA designation. The most common use of Napa County on a wine label is when a wine has been produced from grapes grown in two or more counties, such as Sonoma County

Sonoma County wine

Sonoma County wine is wine made in Sonoma County, California, USA. County names in the United States automatically qualify as legal appellations of origin for wine produced from grapes grown in that county and do not require registration with the United States Department of the Treasury, Alcohol...

and Napa County. In such a case, the wine label must indicate what percentage of grapes were sourced from each county.