It is hard to explain to someone who grew up in a big city in the Northeast just how big a deal college football is in the Southeast.

College sports, and particularly football, occupy a role at the center of daily life in the South — like in South Carolina, where one of us grew up — that is hard to imagine for many people who grew up in New York or Boston.

Last month we published The Upshot’s map of college football fandom, showing where people root for what college teams. That map offers great detail about what teams college football fans root for in a given location, but nothing about how concentrated college football fans are in that place.

Here, we are looking at another question: not which teams fans root for, but the proportion of the population in various places who are fans of any college football team. We asked Facebook to compile that information, and the results offer a portrait of America’s college-football obsession — or lack thereof. To be more specific:

Alabama has the highest concentration of college football fans. This perhaps shouldn’t be surprising, given that the University of Alabama has finished the season ranked No. 1 in the country in three of the last five seasons and that Auburn has finished twice in the top two. It will also not surprise anyone who has read “Rammer Jammer Yellow Hammer,” by Warren St. John. Almost 34 percent of Alabama Facebook users were fans of a college football team, more than five percentage points higher than in the state with the next-highest level.