Area Code 603-554 located in MILFORD, HILLSBOROUGH, NH, more detail is as below. Place NPA (Numbering Plan Area) : 603 NXX (Local Number Prefix) : 554 City : MILFORD County : HILLSBOROUGH State : NH (New Hampshire) NXX Use Type : Wireless NXX Intro Version : 1998-01-25 FIPS (Federal Information Processing Standards) : 33011 LATA (Local Access Transport Area) : 122 Rate Center : MILFORD ZIP Code Count : 0 ZIP Code Frequency : Most frequently occurring ZIP Code, although percentage is unknown. ZIP Code : 03055 Other Information NPANXX : 603554 County Population : 0 Switch CLLI (Common Language Location Identifier) : MRMCNHGICM0 MSA CBSA (Core Based Statistical Area) : Manchester-Nashua, NH MSA CBSA Code (Core Based Statistical Area) : 31700 Time Zone : Eastern (GMT -05:00) Observes Daylight Saving Time : Yes Company : UNITED STATES CELLULAR CORP. - NEW HAMPSHIRE OCN (Operating Company Number) : 6290 Coverage Area Name : MILFORD Latitude : 42.8338 Longitude : -71.6472 ‹ previous : 603-553 next › : 603-556 Telephone Number List 603-554-0000 ~ 603-554-9999