How to handle ego clashes within an academic department I am a new assistant professor in my department. While all faculty members have been welcoming so far to me, I find there are two or three distinct groups or coteries within the department. The coteries are distinct and comprise set of people who wouldn't mingle with people from another coterie. It is a bit awkward for me because there are even senior professors in different sets, and I want to be affable with everyone in my department. 

How do I handle this sense of discomfort? Should I talk with the Chair? But the sectoring is pretty well-known and prevalent for a long time and there is little the Chair can do about it (or so I think!)

How do academic departments handle this situation of clash of egos usually? I am sure mine is not the only place where this clash is seen.
The best advice anyone can give you, in my opinion, is: Don't get involved.

You're entering a new environment and it's in your best interests to just get along with everybody, as you already suggest you are trying.

If the issue pops up in any discussions, just avoid it. The last thing you want to do is get caught-up in a territorial dispute of which you probably don't want to know the origins, and that serves no purpose to anybody, least of all to you.

I would only advise discussing things with the Chair if these divisions start negatively affecting your work, and only discuss it in terms of how it affects your work. As you've pointed out yourself, chances are he/she can't do anything about it, or worse, he/she may be involved.

Things like this can happen even in the best departments, and the best thing that can happen in such a case is that new staff bridge whatever divide may be there by ignoring it completely.