Post Office - Williamstown 120 N West St Williamstown, PA 17098 Phone : (717) 647-9324 Post Office - Williamstown Business Category Post Offices Government Offices & Public Schools Toll-Free           (800) ASK-USPS Us Government--postal Service, Williamstown 120 W Willimstwn Tower City, PA 17980 Phone : (717) 647-9324 Business Category Government Offices-Federal Government Offices & Public Schools