Dunn Howell Mountain is a Napa Valley winery located on Howell Mountain, a sub-appellation of the Napa Valley AVA in California. The winery was established in 1979 by Randy Dunn and his wife, Lori, with the purchase of a 14-acre property on Howell Mountain. Randy Dunn, a winemaker and vineyard consultant, had previously worked at Caymus Vineyards and had developed a reputation for making powerful, age-worthy Cabernet Sauvignon.

Dunn Howell Mountain quickly gained recognition for its high-quality wines, which were characterized by their intense flavors, firm tannins, and ability to age for decades. The winery's focus on Howell Mountain, with its unique microclimate and volcanic soils, allowed Dunn to produce wines with distinct terroir-driven characteristics.

In the early 1990s, Randy Dunn's son, Mike Dunn, joined the winery and took over winemaking duties in 2004. Under Mike's leadership, the winery has continued to produce world-class Cabernet Sauvignon, as well as smaller amounts of Cabernet Franc, Petit Verdot, and other varietals.

Today, Dunn Howell Mountain is considered one of the top producers of Cabernet Sauvignon in the Napa Valley, and its wines are highly sought after by collectors and enthusiasts alike. The winery's commitment to quality and terroir-driven winemaking has helped to shape the modern history of the Napa Valley wine industry.