Located in the Eastern (GMT -05:00) time zone. Area code 617 serves the state of Massachusetts. This area code was assigned on January 1st, 1947. On January 1st, 1947 it went into service. 617 is a General Purpose Code. 617 service area does overlap with 857 area codes. Dialing pattern for local calls within the same NPA (area code) is 10D.