The Howell Mountain AVA is an American Viticultural Area located within Napa Valley AVA of California. The AVA is located in the Howell Mountains within the Vaca Range on the northeast side of Napa Valley around the town of Angwin, and overlooks the town of St. Helena, California. The boundaries of the AVA are dictated by vineyard land located at elevations at least 1,400 feet (430 m).