Area Code 351

Massachusetts

Area code 351 serves Massachusetts, primarily Lowell, in the Eastern Time (ET) time zone. It is an overlay area code sharing territory with area code 978.

Overlay Area Code

This area code is part of an overlay region, meaning the same geographic area is served by multiple area codes. Overlay codes were introduced to meet growing demand for phone numbers without requiring existing customers to change their numbers.

This area code shares its geographic region with: area code 978 (Lowell).

In service since: 02-May-2001

Learn more about overlay and split area codes →

Demographics & Economics

Total Population: 884,136
Population Density: 291 people/sq mi
above U.S. average (U.S.: 93 people/sq mi)
Median Household Income: $70,535
near U.S. median (U.S.: $75,144)
Poverty Rate: 13.6%
above U.S. average (U.S.: 11.5%)
Unemployment Rate: 5.8%
above U.S. average (U.S.: 3.6%)
Education Attainment: Bachelor's Degree+
35.9%
near U.S. average (U.S.: 33.7%)
High School or Lower
31.9%

Statistics are population-weighted aggregations from Census ACS 5-year estimates. Population figures are approximate — see Sources & Methodology for details on how area code populations are derived.

See how this area code compares to all US area codes in the Statistics dashboard.

Time Zone

Eastern Time (ET)

NANPA Relief Status

According to the latest NANPA analysis (July 2026), this area code is not currently listed as exhausting within the next 36 months. No relief planning is in progress for this NPA.

Source: NANPA NPA Relief Planning Reports · See all relief planning statuses

Current Time

Eastern Time (ET)

Prefix Utilization

Geographic Coverage

State

Major Cities

Lowell
Lawrence
Haverhill
Peabody
Salem
Leominster
Beverly
Fitchburg
Gloucester
Danvers
Wilmington
Gardner
Newburyport
Hudson
Maynard
Andover
Athol
Clinton
Pinehurst
West Concord
Salisbury
Ipswich
Rockport
Winchendon

and 23 more cities

Area Code 351 geographic coverage map (light mode)

Historical Timeline of Area Code 351

Area code 351 was created on May 2, 2001, as an overlay for area code 978 in north central and northeastern Massachusetts. It was part of a simultaneous quad overlay: Massachusetts activated four new area codes (857, 774, 339, 351) on the same day, ordered by the Massachusetts Department of Telecommunications and Energy in April 2000. This coordinated approach addressed numbering exhaustion across Eastern Massachusetts, where rapid growth in the late 1990s depleted available prefixes in multiple overlapping area codes. (Source: MA DTE D.T.E. 99-11)

Key milestones:

1988: Area code 508 created from a 617 split (July 1988), serving eastern Massachusetts outside Boston. (Source: Wikipedia)
1997: Area code 978 created from a 508 split (September 1, 1997), covering north central and northeastern Massachusetts. (Source: Wikipedia)
1999: FCC 99-246 delegated authority to MA DTE for area code conservation (September 15, 1999). (Source: FCC Delegation Order)
2000: DTE ordered four overlays simultaneously: 857/617, 774/508, 339/781, 351/978 (April 25, 2000). NANPA issued Planning Letter 234 on July 11, 2000. (Source: MA DTE D.T.E. 99-11)
2000: Permissive 10-digit dialing began across Eastern Massachusetts (September 15, 2000). (Source: NANPA PL-234)
2001: Mandatory 10-digit dialing (April 2, 2001). Area code 351 activated as overlay of 978 (May 2, 2001). (Source: NANPA PL-234)

Regulatory History

Area code 351 was created through five significant regulatory events spanning from 1999 to 2001. The FCC delegated area code authority to Massachusetts DTE in 1999, which then ordered four overlays for Eastern Massachusetts in April 2000. NANPA issued Planning Letter 234 on July 11, 2000, assigning NPA 351 to overlay 978. (Source: NANPA PL-234)

Year	Event	Docket	Regulatory Action & Impact
1999	Delegation Order	CC Docket No. 96-98	FCC delegated authority to MA DTE for TNP and area code conservation for 508, 617, 781, 978. (Source: FCC 99-246)
2000	Area Code Relief Order	D.T.E. 99-11	Ordered creation of four overlays (857, 774, 339, 351); chose overlay over split due to industry support. (Source: MA DTE)
2000	TNP Investigation	D.T.E. 99-99	Concluded TNP insufficient to delay new area codes; estimated $8M cost for early implementation. (Source: MA DTE)
2000	NPA Assignment	PL-234	Assigned 351 as overlay of 978; permissive dialing Sep 15, 2000; mandatory Apr 2, 2001; in-service May 2, 2001. (Source: NANPA)
2001	NXX Rationing	Letter Order	Ordered 978 NXXs exhausted before 351 use; 34 pending 351 requests converted to 978. (Source: MA DTE)