Post Offices in Northfield, Minnesota, United States SearchSearch SearchSearch View: Grid 1View: Grid 2View: Grid 3View: Grid 4View: Grid 5View: List Northfield Post Office No Reviews Favorite Fax: (507) 645-2388Phone: (507) 645-7812Retail Hours Northfield Carrier Annex Post Office No Reviews Favorite Phone: (507) 645-8127Retail Hours