Area Code Atlas

NPA 978 split from 508

Area code 978 was split from 508 on September 1, 1997, serving northeastern Massachusetts. The split was implemented to address the need for more telephone numbers in the region, with the remaining 508 area continuing to serve south-central and southeastern Massachusetts. It includes cities such as Lowell and Lawrence.

Mandatory dialing for NPA 978

The permissive dialing period for area code 978 ended on February 1, 1998, making ten-digit dialing mandatory for all calls within the region. This change followed the 1997 split from 508.

Permissive dialing ended for 978

The permissive dialing period for area code 978 ended on February 1, 1998, requiring callers to use the new area code for numbers in the 978 region.

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

NPA 351 overlay introduced for 978

Area code 351 was added as an overlay to area code 978 on May 2, 2001, covering the same geographic region in north central and northeastern Massachusetts. The overlay required all calls to use ten-digit dialing.

Mandatory ten-digit dialing began for 978/351

Ten-digit dialing became mandatory for all telephone calls in the 978 and 351 area codes on May 2, 2001, coinciding with the introduction of the 351 overlay.