Post Office - New Haven 4250 State Route 104 New Haven, NY 13121 Phone : (315) 963-3166 Post Office - New Haven Business Category Post Offices Toll-Free           (800) ASK-USPS United States Government--postal Service, Local Area Post Offices, New Haven Rr 104 Mexico, NY 13114 Phone : (315) 963-3166 Business Category Government Offices-Federal Post Offices Government Offices & Public Schools