When a U.S. winery wants to tell you the geographic pedigree of its wine, it uses a tag on its label called an Appellation of Origin that provides the geographic origin of where the grapes are grown. Appellations are defined either by political boundaries, such as the name of a county or state, or by federally-recognized growing regions called American Viticultural Areas (AVAs).
Following is a list of AVAs for California. Unless otherwise indicated, all acreage estimates are from the Final Rules published in the Federal Register of the U.S. Government. Final rules for expansions, boundary changes or renamed AVAs are being researched and will be added at a later date.