The Guenoc Valley AVA is an American Viticultural Area in Lake County, California, USA, about 15 mi (24 km) north of the town of Calistoga. Guenoc Valley AVA was the first American Viticultural Area designation granted to an area with just a single winery.Guenoc Valley is a small inland valley comprising an alluvial fan of Arroyo Seco and Conejo Loam series soils isolated from surrounding areas by rocky ridges. Its geographical location also affects the climate.