St Helena is a historic AVA (American Viticultural Area) located in the Napa Valley region in the shadow of the 1325 m asl Mount Saint Helena. St Helena is the birthplace of the of Napa Valley’s commercial wine industry. The viticultural history of St Helena goes back to the 1840s when a Mission was established. In 1873, pioneers Charles Krug and Henry Pellet combined their production to ship the first wines outside California, within a decade, their wines had become popular. St Helena was officially recognised as AVA in 1995.

St Helena has 3600ha of densely planted vineyards with one of the hottest climates in the Napa Valley due to the protection from the western hills, with less fog or wind incursions. The region has a combination of warm days with high winds in the evening creating a massive diurnal shift. The cold nights allow the vines to rest and maintain the acidity producing fruity wines with good colour and reasonably fresh. The region's soil is mainly mixed gravel and clay with lower fertility and moderate water retention, but further north and to the east the soils are prevalently volcanic in origin and deeper and more fertile.

St Helena’s AVA is famous for big, structured and fruity wines made predominantly from Cabernet Sauvignon and to a lesser extent Merlot, as well as small plantings of Cabernet Franc, Syrah, Zinfandel and Sauvignon Blanc.

St Helena is known for some of California's most distinguished and oldest wineries and outstanding wines. Nowadays this is an area with an enormous concentration of investments making the region one of the most modern winemaking area in the world.