The City Clerk's office will be open on Sunday, July 24, 2011 and will have extended hours for the first week that the Marriage Equality Act goes into effect.
In New York City, all couples must wait 24 hours after getting a marriage license to have a marriage ceremony, and the marriage license is typically valid for 60 days. New York City allows both residents and non-residents to marry, so even if you don't live in New York, you can still be married here.
Complete details about getting married in New York City are available on the City Clerk's Website.
NYC & Company, New York City's tourism and marketing agency, has assembled a great list of special NYC I Do: Pride in the City offers for people who want to plan a wedding in New York City.

