The Russian River Valley AVA is located on 155,000 acres in Sonoma County, California. Situated on the Russian River, the appellation was granted AVA status in 1983 and has over 10,000 acres currently under vine. The soil of the Russian River Valley varies by region. Layers of volcanic ash and eroded bedrock have created a sandstone that cover most of the region. Near the Russian River itself, there is alluvial soil, and in the northern most region, clay soil is abundant. The variety of soils gives the Russian River Valley a great range in the profiles of its varietals. The Russian River Valley's feature characteristic is its cool climate, generated by fog and coastal breezes due to the valley's proximity to the Pacific Ocean. The area features varietals known to grow well in cool climates. The region is best known for its Pinot Noir and Chardonnay production.