United States Government--post Offices, Andover 513 5th St Cambridge, IL 61238 Phone : (309) 521-8242 Business Category Government Offices-Federal Post Offices Government Offices & Public Schools Post Office - Andover 513 5th St Andover, IL 61233 Phone : (309) 521-8242 Post Office - Andover Business Category Post Offices Toll-Free           (800) ASK-USPS