Almaden Vineyards, historically written as Almadén Vineyards, is a Californian winery. Founded in 1852, it is the oldest commercial winery in California. Originally located and established in Almaden Valley, San Jose, the winery has since moved to the San Joaquín Valley, primarily based in Escalon and Madera. The Old Almadén Winery in San Jose is a registered California Historical Landmark and open to the public.