The Wine Country is an area of Northern California in the United States known world-wide as a premium wine-growing region. Viticulture and wine-making have been practiced in the region since the mid-19th century. There are over 400 wineries in the area north of San Francisco, mostly located in the area's valleys, including Napa Valley in Napa County, and the Sonoma Valley, Alexander Valley, Dry Creek Valley, Bennett Valley, and Russian River Valley in Sonoma County. Wine grapes are also grown at higher elevations, such as Atlas Peak and Mount Veeder AVAs. The region is defined not only by its viticulture, but also its ecology, geology, architecture, cuisine, and culture. The majority of the grape harvest, by both area and value, derives from Sonoma County.