Number of wineries currently operating in California. The state accounts for 43% of all the wineries in the U.S. but 80% of the wine produced. Admittedly, the California wine industry is the most mature in the country—the number of wineries in the state has grown by only 27% since 2015. By comparison, Texas and Michigan, in the Top 10 most wineries per state, have grown their numbers by 84% and 80% respectively. California’s dominance of the U.S. market makes it the fourth largest wine producer in the world.