The Cole Ranch AVA is an American Viticultural Area located in Mendocino County, California. At less than a quarter of a square mile, it is the smallest appellation in the United States. The AVA is located between the Russian River and Anderson Valley. All planted land in the appellation is owned by one winery, Esterlina Winery, though some of the grapes are sold to other wineries. Cabernet Sauvignon, Merlot and Riesling are the most popular planting.