There are very few schools in America (BYU or something like that comes to mind) where you couldn't be openly gay on campus. The trick is figuring out what aspect of campus life would be accepting. When I was in college, I wasn't out (not technically in the closet though because I hadn't even realized I was gay at this point). I joined a fraternity and although it was a blast, if I had realized I was gay at that point in my life there is no way I would have felt comfortable coming out...rampant homophobia.
Fraternities, athletics teams and religious groups may be less open to being gay. Of course, it depends on the group and the school. It generally seemed that the fraternities that were going through colonization phases were very happy to take gay members and they could even bring their boyfriends to invites and date parties. The fraternities that had been on campus a lot longer (usually much more active socially with more members, bigger parties, nicer houses, etc) tend to be a lot more conservative and will generally not bid openly gay members.
Have fun in college, it is a blast! Push your comfort zone, it's a fantastic time to discover new sides of yourself.