AVA's - American Viticultural Areas of California
Source: Wine Institute using Federal Register Information
An American Viticultural Area (AVA) is a designated grape growing region in the US, distinguishable by geographic features. These AVA's have geographical boundaries defined by the Tobacco and Trade Bureau (TTB). These designations allow vintners and consumers to attribute a given quality, reputation, or other characteristic of a wine made from grapes grown in an area to its geographic region.
As of 2014, there were more than 107 American Viticultural Areas, or federally recognized growing regions, in California, a testament to the variety of microclimates in the state. Wine-type grapes are grown in 46 of California's 58 counties, covering 522,000 acres.