Baseball may be America's pastime, but football is America's religion. The country basically shuts down on Sundays to worship at the altar of touchdown and its patron saints (not to be confused with New Orleans Saints) Manning, Brady, and Rodgers.
Of course, not all teams are created or followed equal. The Cowboys, for example, are known as "America's Team", while the Jaguars are basically nobody's team.
To figure out who's popular where, the data-crunching folks at Twitter analyzed official team handles and their followers to geolocate fans nationwide, as opposed to just who's talking smack or reacting to plays they see on TV. And they dropped that data into a handy-dandy (and super addictive) interactive map.