Thanks to Facebook, the popular social media site maps out team fan support based on where the most fans for each team reside with darker shades representing higher percentages of each team's fans. This represents the cumulative number of people who like the respective team pages.
All four of the teams have fans spanning Northern California but here's where there are the most concentrated number of fans:
· Athletics: Elmira, CA
· Raiders: Fulton, CA
· 49ers: Pacifica, CA
· Giants: Daly City, CA