Hey there!
Well my situation is a little different I suppose because I'm not from a huge university. I go to a college in Boston that has about 2,3000-2,700 students. Most of the sororities and fraternities are local, but we do have a couple national...Here's the run down:
ZETA PHI ETA
ALPHA EPSILON PHI
KAPPA GAMMA CHI
CHI DELTA CHI
SIGMA PI THETA
SIGMA ALPHA EPSILON (Phi Alpha)
ALPHA PI THETA
PHI ALPHA TAU
The sorority I am in (although I am now alumni) has a very strong presence on campus and does a lot of events. Although we are stong in number for a school our size (about 23) numbers don't matter as much as heart and devotion to the sorority. Local or national, as long as you wear your letters proud and respect your organization thats all that really matters