Diamond Creek Vineyards is an American winery founded by Boots and Al Brounstein in 1968 when they acquired just over 30 acres at Diamond Mountain in Napa Valley. At that time, Al and Boots Brounstein were among the very first winemakers in California and Diamond Creek was the first Californian winery dedicated exclusively to Cabernet Sauvignon.

Originally from Minnesota like another famous Californian winemaker, Robert Mondavi, Al Brounstein first went to Bordeaux where he brought back Cabernet vines and received advice from André Tchelistcheff, another famous Napa Valley winemaker, for the choice of soils. He opted for plots located on the hills rather than on the plains like most of Napa's vineyards.

When planting his vines more than 50 years ago, Al Brounstein identified 4 different terroirs: Volcanic Hill with soils covered with white ash from an extinct volcano called Mount Kanati, Red Rock Terrace with red soils rich in iron, Gravelly Meadow with soils of small alluvial pebbles and finally Lake. He is thus one of the pioneers of parcel viticulture in California.

Since Al Brounstein's death in 2002, his wife Boots and son Phil Ross have run the estate.