Thin crust or deep dish. As a Chicagoan, that’s the age-old argument* I’m supposed to jump into with gusto. Truth be told, though, pizza, much like the hamburger, is a food force shaped as much by chains as it is by local traditions. So if you want to know who really rules the pizza heart-share, you need look no further than the most popular generic option.
According to FlowingData, that king of all pizza is Pizza Hut. FD's color-coded map shows the nearest pizza chain within a 10-mile radius across the United States, and that place is most often blazing in Pizza Hut red. Also well-represented is Domino’s blue, which has less of a stronghold in the midwest but dominates the East Coast, and Little Caesars, which sort of blends in with Pizza Hut because it’s rendered in orange.
As always, however, it’s the outliers that are the most interesting. Papa Murphy’s, for instance, has a very strong install base in the Northwest, while Godfather’s holds down much of our country’s core. (In each of these cases, the pizza chains are best represented where they were founded.) Also interesting is just how much of our country's land mass lives more than 10 miles away from the closest pizza chain. Not that our low populations of western friends are missing all that much in terms of breakfast sausage placed alongside pepperoni or garlic dipping sauce that will never congeal, but it must be strange to live within the noise of $10 pizza/wing/breadsticks deals all over the mass media and never have the opportunity to gag up your first bite of a cheeseburger-stuffed crust. And what is partaking in a cheeseburger-stuffed crust pizza other than every patriot's duty who believes in life, liberty, and massive dairy subsidies?
*In reality, Chicagoans do eat deep dish, on occasion. But our more popular square-sliced thin-crust subculture--which is totally different and more delicious than New York’s--is routinely, infuriatingly overlooked by food publications/shows. And it’s way better than the pizza you’ll eat anywhere else in the world, the deep dish you find in Chicago.