Word that describes being "patriotic" for something that is not a country?

I'm looking for a word that is similar to patriotic but does not relate to one's country (or state).

For what it's worth, I'm specifically referring to "overly patriotic" in a negative sense, to describe someone who has a overly sentimental/cultural or otherwise less-than-rational attachment or devotion to something and makes it part of their very identity. A common example might be an extremely zealous football fan.

partisan

From Google:

noun 1. a strong supporter of a party, cause, or person.

Also adjective; the abstract noun is partisanship.

This addresses the question in the title and first paragraph.

When talking about ideology, the word zealot is commonly used to imply an obsessive (often negative) devotion.

It can be used for sports fanatics, although I wouldn't use it for something like ethnicity or nationality (which is more something you are than an idea/ideal you ascribe to).

And of course, the word fanatic also works in many cases.

chauvinist

chauvinist: 2 : person with an undue partiality or attachment to a group or place to which he or she belongs or has belonged.

Consider also sectionalist.

sectionalist: person with excessive or narrow minded concern for local or regional interests as opposed to the interests of the whole.

"Sports teams develop a sense of sectionalism among US citizens."