Just in time for Opening Day, the Facebook data team has released a map showing which MLB teams have the most Facebook fans, by county.
Sadly—although not surprisingly—Yankees fans appear to be a de facto national team, popular wherever there's no one obvious to root for. They completely overshadow the Mets, just as the A's are overshadowed by the Giants in the Bay Area, and destroy the Marlins in South Florida.
Baseball team colors are overwhelming red and blue, so you'll have to forgive some of the creative licenses the designers took here to make this map legible (although Nationals/Orioles is still tough). How does your team's territory look?