351 Area Code: Lowell, Lawrence & Northeast Massachusetts

The 351 area code is the overlay that shares northeast Massachusetts with 978 — the Merrimack Valley and Cape Ann region anchored by Lowell, Lawrence, and Haverhill. Added in 2001, it covers the same north-central and northeastern corner of the state, from the old mill cities along the Merrimack River out to the fishing port of Gloucester. One quick note up front: as a US area code, 351 is not the same as Portugal's +351 country code.

This guide covers where the 351 area code is, the Portugal mix-up, how it overlaid 978, how the two codes work together, Lowell's industrial-revolution heritage, dialing, and how to get a 351 number.

Where is the 351 area code?

The 351 area code location is north-central and northeastern Massachusetts — the same area as 978. It sits north and northwest of Boston, reaching the New Hampshire border and the Atlantic coast at Cape Ann.

Cities and communities inside the 351 / 978 footprint include:

Is 351 a Portugal or European country code?

This is the most common point of confusion, so let's clear it up: 351 is a US area code in Massachusetts — it is not Portugal. The mix-up happens because +351 is the international country code for Portugal, so a number written +351 … is Portuguese, while a US number is written +1 351 …. The two look similar but the leading country code is different. If you see a "+1 351" number, it's northeast Massachusetts; a "+351" number is Portugal.

How 351 overlaid 978

Northeast Massachusetts has changed codes in two steps:

• 1997: 978 splits off. This region was originally part of 508. As demand grew, 978 was created to serve north-central and northeastern Massachusetts.
• 2001: the 351 overlay. A few years later, 978 was running short of numbers. Rather than split the region again, regulators added the 351 overlay across the entire 978 area, and ten-digit dialing became mandatory.

Existing 978 numbers were untouched; 351 simply adds a fresh supply for the same area.

How 978 and 351 work together

Because 351 overlays 978, the two codes cover identical ground — neither signals a different town or carrier:

• Your existing 978 number does not change.
• Newer lines may be assigned 351, while established ones keep 978.
• Ten-digit dialing is required on every call, even local ones.
• Calls between 978 and 351 are local, with no long-distance charge between them.

The 351 code has no territory of its own — it exists only as the overlay on the 978 area code.

Lowell and the Merrimack Valley

The 978/351 region has a remarkable industrial story and a modern economy to match:

• Industrial heritage — Lowell is widely called the birthplace of the American Industrial Revolution, its 19th-century textile mills now preserved as Lowell National Historical Park.
• Technology and manufacturing — the region grew into a high-tech and advanced-manufacturing corridor north of Boston, with plastics in Leominster and electronics across the valley.
• Healthcare and education — UMass Lowell, Fitchburg State, and regional hospital systems anchor the metro areas.
• Coastal and tourism — Gloucester's fishing fleet and Newburyport's waterfront support a coastal economy on Cape Ann.

For manufacturers, tech firms, healthcare groups, and professional services, a 978 or 351 number reads as genuinely northeast-Massachusetts.

351 time zone and dialing

The 351 area code time zone is Eastern Time (ET) — EST (UTC−5) in winter and EDT (UTC−4) in summer, the same clock as Boston and New York. Because 351 shares an overlay with 978, ten-digit dialing is required on every call, including from cell phones. A 351 number works for calls and texts on mobile just like any US number: dial 1 351 XXX XXXX from elsewhere in the US, or +1 351 XXX XXXX internationally and from mobiles.

Putting a 351 number to work for your business

A 351 number puts a northeast-Massachusetts address on your caller ID without a local lease. For manufacturers, tech firms, healthcare groups, and professional services selling into the Merrimack Valley, a local code reads as familiar and lifts answer rates over an unknown out-of-state or toll-free line.

You do not need a Lowell office to claim one. A cloud phone provider can assign you a 351 number that rings and texts on your existing devices and routes calls anywhere. With a provider like My Country Mobile, you can pick a 351 line, set up routing, an auto-attendant, and voicemail, and be live in minutes.

Staying safe from spoofed 351 calls

Scammers spoof 351 numbers — faking a northeast-Massachusetts prefix, sometimes matching the first digits of your own number — so a call or text looks local. A 351 on your screen does not prove the contact is really in Massachusetts.

A few habits keep you safe:

• Let unknown 351 or 978 calls go to voicemail, and don't tap links in unexpected texts.
• Never share one-time codes, card numbers, or login details with an inbound caller or texter.
• Be skeptical of "utility shutoff," "package delivery," or "your account is compromised" messages that pressure you to act fast.
• Use carrier spam filtering. The FCC's STIR/SHAKEN call authentication framework is why many phones now label these as "Spam Risk."

Key takeaways

• 351 overlays 978 across northeast Massachusetts — Lowell, Lawrence, and Haverhill.
• It was added in 2001, after 978 split from 508 in 1997.
• It is a US Massachusetts code, not Portugal's +351 country code.
• Lowell is the birthplace of the American Industrial Revolution; the region runs on tech, manufacturing, and healthcare, on Eastern Time.
• You can get a 351 number from the cloud without a Massachusetts address.

Frequently asked questions