Area Code 617-370 located in CHELSEA, SUFFOLK, MA, more detail is as below. Place NPA (Numbering Plan Area) : 617 NXX (Local Number Prefix) : 370 City : CHELSEA County : SUFFOLK State : MA (Massachusetts) NXX Use Type : Landline NXX Intro Version : 1998-01-25 FIPS (Federal Information Processing Standards) : 25025 LATA (Local Access Transport Area) : 128 Rate Center : CHELSEA ZIP Code Count : 0 ZIP Code Frequency : Most frequently occurring ZIP Code, although percentage is unknown. ZIP Code : 02150 Other Information NPANXX : 617370 Switch CLLI (Common Language Location Identifier) : CMBRMAMQDS0 MSA CBSA (Core Based Statistical Area) : Boston-Cambridge-Quincy, MA-NH MSA CBSA Code (Core Based Statistical Area) : 14460 Time Zone : Eastern (GMT -05:00) Observes Daylight Saving Time : Yes Company : XO MASSACHUSETTS, INC. OCN (Operating Company Number) : 4536 Coverage Area Name : CHELSEA Latitude : 42.3676 Longitude : -71.0867 ‹ previous : 617-369 next › : 617-371 Telephone Number List 617-370-0000 ~ 617-370-9999