The largest producing province, 75% of total vineyard area, 70% of production. Mainly in valley of river Mendoza, but extending to foothills of the Andes from 500m to 1500m (Uco Valley) above sea level 60% black varieties, dominated by Malbec (30+%) Only two DOCs, and a lot of GIs (GI Cuyo covers the whole area). 5 separate divisions, each own distinct character: Northern - low altitude 500-700m Eastern - low altitude Central: the Primera Zona Uco Valley Southern