Most popular team on Facebook from 2009 to 2014 Since April 1, 2015

When we published a national map of baseball fandom last year, based on Facebook data, it contained a painfully sad fact for Mets fans: In every ZIP code across every borough of New York, the Yankees were more popular than the Mets.

The same was true on Long Island and in Westchester, northern New Jersey and Connecticut, and the same remains true today, with the Mets unable to claim the most total likes in any ZIP code.

But now we come back to Mets fans with better news: The team has increased its footprint across the city in 2015, and, among new fans, the Mets were the most popular team across much of Brooklyn and Queens and on most of Long Island.

The Mets’ gains were not limited to the New York area. Baseball fans across the country made some extra room in their hearts for the Mets this year – perhaps because of an unexpected second-half run led by four of the league’s 20 hardest-throwing pitchers.

New Royals fans

About 1,000 miles west of New York, the Kansas City Royals don’t have the same kind of local competition, with the Rockies and the Cardinals both hundreds of miles away. But the Royals began to expand their fan footprint in 2015, pushing well into western Kansas and Nebraska, and expanding into central Missouri.

Mets vs. Royals

The 2015 World Series doesn’t stir any deep rivalry among fans. But for those who wonder, here’s how the Mets-Royals fan matchup plays out everywhere in the United States.

Finally, a reminder on how we make these maps: Pinning down regional sports allegiance can be an inexact science. Fans don’t make their preferences known on, say, the census, and polls of team preferences are scarce. But millions of fans do make their preferences public on Facebook by “liking” a team. Using data aggregated by the company, we measured fans’ allegiance to a team in each ZIP code. To get numbers for the most recent fans, we looked at “likes” over the last six months. We then applied an algorithm to smooth the data and fill in gaps where data was missing. (Imperfect as Facebook “likes” are, they do broadly line up with other data.)