Area Code Atlas

NPA 781 split from 617

Area code 781 was split from 617 on September 1, 1997. This split removed the northern, western, and southern portions of the 617 area, creating a code that almost completely surrounds 617 and covers the Boston suburbs. The split was implemented to provide additional numbering resources for the growing metropolitan area, taking over the northern, western, and southern suburbs of Boston and leaving 617 largely coextensive with the inner ring of Greater Boston.

Mandatory use of area code 781

Beginning February 1, 1998, use of area code 781 became mandatory for calls within its service area. This marked the end of the permissive dialing period following the 1997 split from 617.

Extraordinary Jeopardy Procedures for 508, 617, 781 and 978 Numbering Plan Area (NPA) in Massachusetts

Activation of area code 339 as overlay for 781

On May 2, 2001, area code 339 was activated as an overlay for the 781 region in Massachusetts. This overlay required ten-digit dialing for all calls within the area, providing additional numbering resources for the same geographic region.

Ten-digit dialing becomes mandatory in 781/339 overlay complex

As of May 2, 2001, ten-digit dialing became mandatory for all calls within the 781 and 339 area codes due to the activation of the 339 overlay. This change affected all customers in the overlay region.