Area Code 339-205 located in MIDDLESEX, MIDDLESEX, MA, more detail is as below. Place NPA (Numbering Plan Area) : 339 NXX (Local Number Prefix) : 205 City : MIDDLESEX County : MIDDLESEX State : MA (Massachusetts) NXX Intro Version : 1/5/2012 Rate Center : WALTHAM ZIP Code Count : 0 ZIP Code Frequency : 0 Other Information NPANXX : 339205 County Population : 0 Time Zone : Eastern (GMT -05:00) Observes Daylight Saving Time : Yes Latitude : None Longitude : None ‹ previous : 339-204 next › : 339-206 Telephone Number List 339-205-0000 ~ 339-205-9999