The Napa Valley American Viticultural Area (AVA) is a federally designated wine region within Napa County, California. It was approved by the U.S. Bureau of Alcohol, Tobacco and Firearms on January 28, 1981, following an August 1978 petition from the Napa Valley Vintners and the Napa Valley Grape Growers Association, making it the second AVA established in the country and the first in California.
The appellation covers all of Napa County except the area northeast of Putah Creek and Lake Berryessa — a relevant boundary detail for the Zodiac case, since the September 1969 Lake Berryessa attack occurred at that lake on the edge of the wine region. The valley floor lies between the Mayacamas Range to the west and north and the Vaca Mountains to the east, rising from sea level in the south to higher ground near Calistoga at the base of Mount Saint Helena.
The region’s commercial viticulture dates to the nineteenth century, with George C. Yount recorded as the first to plant vines (1838), John Patchett founding the first commercial vineyard (1858), and Charles Krug establishing an early winery at St. Helena (1861). Modern premium production reemerged in the 1960s and gained international attention at the 1976 Paris Wine Tasting. As of 2024 the AVA contains seventeen sub-appellations and draws more than 4.5 million visitors annually.
Note: This page documents the geographic wine region only and has no established connection to the Zodiac case beyond its overlap with the Lake Berryessa area.