Post Office - De Witt 711 Jefferson St De Witt, MO 64639 Phone : (660) 549-3421 Post Office - De Witt Business Category Government Offices-Federal Post Offices Government Offices & Public Schools Toll-Free           (800) ASK-USPS United States Government--post Offices, De Witt, For Zip Code Information De Witt, MO 64639 Phone : (660) 549-3421 Business Category Government Offices-Federal Post Offices Government Offices & Public Schools