They live within or close to the city that team is stationed in. Some follow a team because they grew up with them / their parents are die hard fans. Others follow them because they jumped on a band wagon when they were once a good team and they felt they should stick with them. Others feel emotionally attached to one team. Many people have different reasons. I was one of the band wagon because I did not like my local teams. My team is horrible now, but I'm not going to be fake and switch to a different team. Sports teams need loyal fans.