Over the past twenty years, the total number of wineries in the nation has doubled, with wineries located in all 50 states. Grapes are the highest value fruit crop in the country and the sixth largest crop overall. Vineyard prices in Sonoma County, California peak at $85,000 an acre; in nearby Napa County, vineyards peak at $180,000 an acre, representing the nation?s most expensive agricultural land. Currently, there are more than 7,000 brands of wine sold in the United States..