| Chalk Hill AVA | |
| Type: | American Viticultural Area |
| Year: | 1983, amended in 1988[1] |
| Country: | United States |
| Part Of: | California, North Coast AVA, Northern Sonoma AVA, Russian River Valley AVA, Sonoma Coast AVA, Sonoma County |
| Soil: | Volcanic |
| Planted: | 1000acres |
| Grapes: | Cabernet Sauvignon, Chardonnay, Malbec, Merlot, Petit Verdot, Pinot gris, Sangiovese, Sauvignon blanc, Sauvignon gris, Semillon, Syrah, Zinfandel |
The Chalk Hill AVA is an American Viticultural Area (AVA) located in Sonoma County, California. The boundaries of the wine appellation cover the northeast corner of the Russian River Valley AVA. The majority of vineyards are located to the east of U.S. Route 101, near the town of Windsor. The name Chalk Hill comes from the unique volcanic soil of chalky white ash which has shown itself to perform well with planting of white wine varietals like Chardonnay and Sauvignon blanc. The majority of the region's wineries are located on the western slopes of the Mayacamas Mountains.[2]
The boundaries of the Chalk Hill AVA cover 33sqmi of land within the northeast corner of Russian River AVA. Many of the region's 1600acres of planted vineyard land is located along the western slopes of the Mayacamas Mountain reaching up to altitudes of 200–1300 feet (60–400 meters). Compared to the rest of the Russian River Valley, the Chalk Hill region is relatively warm due to the influence of a thermal belt that runs through the area. Harvest time often takes place in September while harvest in the surrounding regions usually takes place in October.[3]
The area takes its name from the "chalky" white soils of the region. However the soils themselves do not contain any chalk but rather are composed of a mixture of quartzite abundant volcanic ash, sand and silty loam. The volcanic was emitted into the area by Mount St. Helena over a course of centuries, creating vineyard soils that are not very fertile and are able to restrain vigor in the vines.[3]