Post Offices in Hauppauge, New York, United States SearchSearch SearchSearch View: Grid 1View: Grid 2View: Grid 3View: Grid 4View: Grid 5View: List Hauppauge Post Office No Reviews Favorite Fax: (631) 366-4621Phone: (631) 360-7229Retail Hours Hauppauge Industrial Park Post Office No Reviews Favorite Fax: (631) 348-4583Phone: (631) 231-3155Retail Hours