Facebook has put their massive data trove to use and examined the geographies of NFL fandom. Here is what they came up with:

The National Football League is one of the most popular sports in America with some incredibly devoted fans. At Facebook we have about 35 million account holders in the United States who have Liked a page for one of the 32 teams in the league, representing one of the most comprehensive samples of sports fanship ever collected. Put another way, more than 1 in 10 Americans have declared their support for an NFL team on Facebook…

While winning seems to matter, NFL teams have local followings that are probably heavily influenced by family ties and/or where a person grew up,  so we were obviously curious to see where the fans for various teams live now. By considering the physical locations of NFL fans, we can construct a map of the top team for each county in the US. It tells an interesting story about the ways that football rivalries and allegiances alternately divide and unite the country, and sometimes even individual states.

In some cases, whole states and even entire regions of the country uniformly support a single team.  For instance the Vikings are easily the only game in town in Minnesota, while New England appears to be comprised of entirely Patriots fans except for a small portion of Connecticut.

There are some states which are divided into regions by teams.  Florida has three teams–the Tampa Bay Bucs, Miami Dolphins, and the Jacksonville Jaguars–and Facebook users there seems fractured in their support, with some counties even defecting to teams from the North. Ohio is another interesting story, with the Cleveland Browns in the North, Cincinatti Bengals in the South, and Pittsburgh Steelers fans occupying the middle of the state.

Some teams, like the Steelers, Cowboys, and Packers, seem to transcend geography, with pockets of fans all over the country. On the other end of the spectrum, the Jets have to share New York with the Giants and are only the most popular team for a single stronghold county in Long Island.

Five quick thoughts:

1. There are few other organizations that could put together such a map without undertaking a major survey (since this is measured at the county level).

2. The best part for Facebook: users voluntarily provided this data.

3. Could Facebook end up being the most important future source for telling us about American society? There are still difficulties: users have to opt in (in this particular case, they had to “like” a NFL team), not everyone is involved (though it seems like pretty close), and not all users are putting everything in their profiles.

4. Is there a way to weight this map with population density? For example, the Cowboys may have a really broad geographic reach but many of those counties have fewer people. In contrast, teams like the Jets or Eagles have smaller reaches yet more people live in those areas.

5. Is there a way to show the percentage of county respondents who liked the dominant team? I imagine there are plenty of counties where one team does not have a strong majority, let alone even much of a plurality. For example, Jets fans barely show up on the map because they are only the top team in one county. Yet, there are plenty of Jets fans.