Panhellenic Council (CPH) sorority recruitment is formal, and requires you to register. Each fall, all of the Panhellenic Council sororities have recruitment at the same time. When you register for recruitment, you are assigned a Recruitment Guide (also called a “Rho Gamma”). This Recruitment Guide guides you through the entire recruitment process from start to finish.
Recruitment is over a weekend: October 20 - 24. During this time, you meet sorority members and learn about each sorority. Sorority recruitment is a “mutual selection process”: after each day of recruitment, you preference your favorite sororities and the sororities do the same for the women going through recruitment. Your preferences narrow down until the final day of recruitment, “Bid Day,” when it is revealed which sorority invites you to join. 99% of women going through recruitment are matched to a sorority and join.
Some sororities may continue to recruit after fall recruitment. But this varies from year to year. So your only guarantee to check out every sorority is to participate in fall recruitment.
“Referral” or “reference” letters are not required to participate in sorority recruitment (this is done at some universities).
If you want to know what sororities are at the University of Cincinnati, go to Current Fraternities and Sororities. Info about each sorority and links to their own website can be found here as well.