i can't really say that i live in a "city" per say, kennett square just isn't that big. and for the most part, martial arts isn't very popular. i would say the biggest school there is a TKD/KravMaga school. most of the people there are people who want to try out KravMaga after seeing one of their ads, commercials, web advertisments, newspaper or magazine articles, the list goes on. Those Krav guys really know how to advertise and have mastered the business end of the art.
i'm close to wilmington, delaware however, where the arts are a little more popular. i can't really say who is the biggest there though. there is such a wide variety, i don't think there is one style that is bigger than the other. that sounds like a good thing to me.