The Bronx has more than 25 zip codes so I chose 10451 at random.
Using the AMA club search http://www.modelaircraft.org/clubsearch.aspx there are 29 clubs within 25 miles of the post office. Some have web sites and email addresses. All have a phone number; hopefully it is current. Many have a link for flying site details.

I do not know what your transportation situation is so a site that is 20+ miles away may not be an option. I drive 45 miles each way to the flying site.