High Valley is an American Viticultural Area (AVA) located in the eastern part of Lake County, California. True to its name, the valley is situated on high elevations ranging from 1,600 feet (490 m) to 3,000 feet (910 m), but it actually encompasses two distinct growing regions, the valley floor and the hillsides. The cool marine breezes are consistently sifting into the valley, keeping the valley cooler than the other appellations in Lake County. Red volcanic soils can be found on the hillsides while alluvial fans and benches on the valley floor provide well-drained beds for the vines. Red Bordeaux varietals and Syrah can be found planted along warmer ridges, while the cooler valley floor contains Pinot grigio, Pinot noir, Chardonnay, Riesling and Sauvignon blanc.

The valley itself is 9 miles (14 km) long and 3 miles (4.8 km) wide, with an east–west orientation unusual in the Californian coastal range, a result of volcanic activity of Round Mountain, an extinct volcano lying within the valley. The AVA contains 15,000 acres (61 km), and about 700 acres (2.8 km) are currently planted in vineyards. Most are relatively new, but within the area are some of the oldest vines in California. There are 15 struggling Zinfandel and Muscat vines planted by the Ogulin family, which brought them from Slovenia around 1875. Since Slovenia borders Croatia, where cousins of Zinfandel vines are found, this suggests significance in the history of California Zinfandel. The old vines shouldn't be a surprise, for before Prohibition, Lake County was producing reputable wines before the vineyards were replaced with other crops.

Significant vineyard holders in the AVA include Brassfield Estate Winery, which estate sits on the valley floor and Shannon Family of Wines.

39°02′53″N 122°42′26″W / 39.0480°N 122.7073°W / 39.0480; -122.7073