I grew up near Baltimore, Maryland (USA), and spent a few years living in the city. One very popular beer in Baltimore is National Bohemian ("Natty Boh" in local parlance). You can see the beer's one-eyed mascot, Mr. Boh, all over the city. Apparently more than half a million cases of Natty Boh are sold in the city of Baltimore each year, which seems pretty high for a city with population 620,000.
One thing that I've found very odd is that outside of the small state of Maryland, you really can't find the beer at all, and 90% of the beer's sales are within the city of Baltimore. Thus, while the beer is reasonably popular, the interest is hyper-localized to a single city.
Are there other examples of beers that have high sales volume but are hyper-localized, or are Baltimore and Natty Boh unique in this respect? Is there some sort of economic or marketing phenomenon behind hyper-localized popularity of a high-volume beer?