It's interesting that the Raiders are still popular in Los Angeles, though they are now in Oakland. There's also a big swath of Cowboy country in Nevada. One county in central Missouri also has a lot of fans of the Dallas Cowboys. That looks like Pulaski County, if I'm reading the map correctly.
I would like to note that the depiction of Alabama is misleading. The state doesn't belong to the New Orleans Saints, but the Crimson Tide and the Tigers--college football teams.
-via Joe Carter