Pizza and demographics aren't normally thought of together, but I chanced upon a year-old Gawker blog post by Max Read which invites demographic analysis. Read, writing perhaps tongue-in-cheek, identifies what he calls the Official Pizza Belt, defined as “the area of the United States where the chance of obtaining an adequate-to-good slice of pizza from a randomly chosen pizzeria is greater than 50 percent.” It runs from Providence, R.I., sweeping through all of Connecticut, all of New York south of Franklin Roosevelt’s Hyde Park, all of New Jersey, metro Philadelphia in Pennsylvania and reaching to the far northeastern edge of Delaware.

If you reduce the chances to one in three, Read writes, the Greater Pizza Belt extends northward to Boston and Albany, N.Y., and southwest to D.C.

As you might expect, these Pizza Belts are highly correlated with demographics. The Historical Census Browser developed by the University of Virginia enables one to quickly calculate the percentage in 1940 of each state’s total population born in Italy (actually, it’s “whites born in Italy”). About 1.2 percent of Americans in that census year were born in Italy and, lo and behold, the states with the highest percentages were in Max Read’s Pizza Belts: Connecticut (4.8 percent), New York (4.3), New Jersey (4.1), Rhode Island (4.0), Massachusetts (2.6) and Pennsylvania (2.0). Indeed, 73 percent of persons born in Italy lived in those six states.

Italian-Americans are still heavily concentrated in these states, which contain 48 percent of Americans who told 2010 census takers that they were of Italian ancestry. Only four other states in 1930 had above-average percentages of persons born in Italy: Delaware (1.3 percent), partially included in the Greater Pizza Belt; Illinois (1.2), of which Read writes, “Chicago is not in the Pizza Belt. I have no desire to discuss Chicago-style pizza”; Nevada (2.0), which had only 110,000 people in 1940; and California (1.5).

Demography is destiny, as the old saying goes. At least in pizza, that appears to be the case, at least if you trust Max Read’s judgment. I was disappointed, however, to see no reference to the fact that in New Haven, Conn., pizzerias carry the label “apizza.” Surely any pizza aficionado has been to Wooster Square and knows that.