Post Offices in Frederick, Maryland, United States SearchSearch SearchSearch View: Grid 1View: Grid 2View: Grid 3View: Grid 4View: Grid 5View: List College Estates Post Office No Reviews Favorite Fax: (301) 846-4674Phone: (301) 624-8050Retail Hours Frederick Post Office No Reviews Favorite Fax: (301) 624-8070Phone: (301) 624-8050Retail Hours