A pleasant way to while away a few minutes (or hours if you’re really into it) is to visit the American Viticultural Area Map Explorer hosted by the Treasury Department’s Alcohol and Tobacco Trade and Tax Bureau, aka the TTB.

The greatest concentration of these official wine regions — the easier-going cousins of France’s appellations d’origine controlee — is, not surprisingly, in California. So is the most famous one, the Napa Valley American Viticultural Area. But most other states now have them, too.

The biggest appears to be the Ozark Mountains AVA, which covers about 55,000 square miles (142,000 square kilometers) in Arkansas, Missouri and Oklahoma; the smallest is reputedly the Cole Ranch AVA in California’s Mendocino County, which is less than a quarter of a square mile and is owned in its entirety by a guy named Mike.