Guenoc Valley AVA
| Wine region | |
| Type | American Viticultural Area |
|---|---|
| Year established | 1981 |
| Years of wine industry | 146 |
| Country | United States |
| Part of | California, North Coast AVA, Lake County |
| Other regions in California, North Coast AVA, Lake County | Big Valley District-Lake County AVA, Clear Lake AVA, High Valley AVA, Kelsey Bench-Lake County AVA, Red Hills Lake County AVA, Upper Lake Valley AVA |
| Climate region | Region III |
| Precipitation (annual average) | 45 to 50 inches (1,143–1,270 mm) |
| Total area | 4,396.3 acres (7 sq mi) |
| Size of planted vineyards | 340 acres (140 ha) |
| No. of vineyards | 1 |
| Grapes produced | Cabernet Sauvignon, Chardonnay, Malbec, Marsanne, Merlot, Petite Sirah, Petit Verdot, Sauvignon Blanc, Semillon, Syrah and Viognier |
| No. of wineries | 1 |
Guenoc Valley is an American Viticultural Area (AVA) in southern Lake County, California about fifteen miles (24 km) north of the town of Calistoga and six miles (10 km) east of Middletown. It was established as the nation's sixth, the state's fourth and the county's initial appellation on November 19, 1981 by the Bureau of Alcohol, Tobacco and Firearms (ATF), Treasury after reviewing the petition submitted by Orville T. Magoon, a single wine grape grower in the valley proposing the viticultural area named "Guenoc Valley."
Basically, the viticultural area compromises 4,396.3 acres (7 sq mi) located south of McCreary Lake and east of Detert Reservoir. It lies in a small inland valley on an alluvial fan of Arroyo Seco and Conejo Loam series soils isolated from surrounding areas by rocky ridges. Its geographical location affects the climate with slightly less rainfall than the nearby Middletown area. Guenoc Valley receives approximately 45 to 50 inches (1,143–1,270 mm) precipitation annually while Middletown receives approximately 60 inches (1,524 mm). Guenoc Valley also experiences slightly greater seasonal temperature extremes being warmer in the summer and colder in the winter. Due to the surrounding ridges, fog is generally less severe than in Middletown. For these reasons, the ATF determined Guenoc Valley possesses geographical features that define it as a viticultural area. Guenoc Valley is the first appellation designation with just a single winery. The plant hardiness zone ranges from 9a to 9b.