Zip Code Information 1640 8th Ave Baldwin, WI 54002 Phone : (715) 684-2934 Business Category Government Offices-Federal Government Offices & Public Schools Post Office - Baldwin 1640 8th Ave Baldwin, WI 54002 Phone : (715) 684-2934 Business Category Government Offices-Federal Post Offices Government Offices & Public Schools Toll-Free           (800) ASK-USPS Fax           (715) 684-4685