The Sonoma Valley AVA has a unique terroir thanks to Sonoma Mountain protecting it from the wet and cool influence the Pacific Ocean has over the other regions of Sonoma County. Historically, Sonoma Valley has been hugely important in shaping California wine. The first vineyards were planted by Franciscan monks in 1823, and Buena Vista Winery was one of the first commercially successful California wineries. Also including the town of Sonoma, Sonoma Valley has more than 250 wineries producing a huge variety of wines from its 65,000 acres of vines.