Area codes 978 and 351

Area codes 978 and 351 are telephone area codes in the North American Numbering Plan for north central and most of northeastern Massachusetts.

A permissive dialing period ended on February 1, 1998.

Prior to when this area was served by 508 (July 1988), it was served only by area code 617, along with the rest of the eastern two-thirds of the state.

Some mobile phone numbers from the 1990s assigned to rate centers in 978 and 351 kept the 508 area code just on those mobile lines after it was split.

The service area extends in north central and northeastern Massachusetts, and comprises the following towns and cities.