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.