Knights Valley is an American Viticultural Area (AVA) located in Sonoma County, California. As one of the five original viticultural areas in the county, Knights Valley was established on October 21, 1983 by the Bureau of Alcohol, Tobacco and Firearms (ATF), Treasury after reviewing the petition submitted by The Knights Valley Wine-Growers Committee, an organization of grape/wine industry members, signed by 16 persons, to establish a viticultural area in northeastern Sonoma County named "Knights Valley." The area encompasses approximately 36,240 acres (57 sq mi) with over 30 growers cultivating 2,000 acres (809 ha) under vine. In the easternmost Sonoma County region, Knights Valley has the warmest climate in the county. The northernmost section of the boundary line runs slightly to the north of Pine Mountain; the southernmost section of the boundary line borders the petrified forest area immediately to the north of Porter Creek. The Sonoma County line bordering Lake County and Napa County forms the eastern section of the boundary of the viticultural area. The easternmost section of the boundary line abuts the boundaries for the Alexander Valley and Chalk Hill viticultural areas. The appellation is the border separating Sonoma County from the Napa Valley.

In 1843, a 17,742-acre (27.722 sq mi) land grant was given to Jose de los Santos Berryessa as a reward from the Mexican Governor for his years of good service. Known as Mallacomes Valley and Agua Caliente (presently Calistoga) was within this grant. The valley became Berryessa's private hunting preserve where he built an adobe hunting lodge that remains to this day. In 1850, after the Mexican War, California became part of the United States and most of the Spanish settlers including Berryessa returned to Mexico.

Thomas B. Knight, a native of Maine and participant in the Bear Flag Revolt at Sonoma bought a large portion of Rancho Mallacomes from Berryessa and received title to the land in 1853. He named it Rancho Muristood, added a second story to the lodge and planted vineyards, peaches, apples and wheat. Mallocomes Valley would later be renamed "Knights Valley." It’s been documented that Knight grew 17 acres of wine grapes, thought to have been planted in 1874, and shipped to the Napa Valley.

Protected from direct Pacific Ocean influence, the valley is the warmest of Sonoma County's viticulture areas. Warm afternoons and cool evenings provide the ideal environment for growing Bordeaux grape varieties. Cabernet Sauvignon remains the star in the valley. Also present are the rest of the Meritage blend: Merlot, Cabernet Franc, Malbec, and Petit Verdot, as well as Sauvignon blanc, Chardonnay, Viognier, Syrah, and some limited plantings of other varietals.

Several producers make wine with the Knights Valley AVA designation. The three largest producers of Knights Valley AVA designated wines are Beringer Vineyards, Kendall Jackson Winery, (under its Highland Estates label), and Bavarian Lion Vineyards.

• Sonoma County AVAs
• TTB AVA Map

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