In an ever-more-competitive global market, vignerons compete for the attention of consumers by trying to differentiate their product while also responding to technological advances, climate changes and evolving demand patterns. In doing so, they highlight their regional and varietal distinctiveness. This paper examines the extent to which the winegrape varietal mix varies within and among states of the United States and relative to the rest of the world, and how that picture has been evolving. It reports varietal intensity indexes for different regions, indexes of similarity of varietal mix between regions and over time, and price-based quality indexes across regions and varieties within and among the three west-coast States. Broadly speaking, the mix of winegrape varieties in the United States is not very different from that in the rest of the world and, since 2000, it has become even less differentiated and closer to that of France and the world as a whole. But individual U.S. regions vary considerably in the mix of varieties in which they specialize and in the quality of grapes they produce of a given variety; and region-by-variety interactions have complex influences on the pattern of quality and production. We use measures of regional varietal comparative advantage and a Nerlovian partial adjustment model to account for some of the shifting varietal patterns in the U.S. vineyard and in winegrape production.