The 351 area code is an overlay covering northeastern Massachusetts. Introduced in 2001, it was layered directly on top of the existing 978 area code to meet growing demand for phone numbers across the Merrimack Valley and North Shore, serving the same cities including Lowell, Lawrence, Haverhill, and Gloucester.
Quick Summary of the 351 Area Code
| Area Code | 351 |
| State | Massachusetts (MA) |
| Region | Northeastern Massachusetts / Merrimack Valley |
| Major Cities | Lowell, Lawrence, Haverhill, Fitchburg, Andover, Methuen, Gloucester, Leominster |
| Time Zone | Eastern Time (ET) – EST / EDT |
| Dialing Format | 10-digit dialing required |
Geographic Coverage
The 351 area code shares an identical geographic footprint with 978, spanning the Merrimack Valley (Lowell, Lawrence, Haverhill, Methuen, Andover), the Fitchburg-Leominster region, and the North Shore including Gloucester. Because it is an overlay rather than a separate region, a 351 number and a 978 number can exist on the same street.
Time Zone
The 351 area code observes Eastern Time (ET). Clocks follow Eastern Standard Time (UTC−5) in winter and shift to Eastern Daylight Time (UTC−4) from mid-March through early November. If you are coordinating a call from the West Coast, remember that this region is three hours ahead of Pacific Time, so a 9:00 AM call in California reaches a 351 number at 12:00 PM local time.
Tip: Business hours across the 351 region generally run 9:00 AM to 5:00 PM Eastern Time, Monday through Friday.
How to Dial a 351 Number
Because area code 351 operates as part of an overlay, 10-digit dialing is mandatory for every local and long-distance call. You must dial the full 10-digit number (351 + the seven-digit line number) even when calling a neighbor across the street. For international callers, dial your country’s exit code, then +1 (the North American country code), then 351, followed by the seven-digit local number.
Scam Alerts for the 351 Area Code
Like every U.S. area code, 351 has been used by scammers who spoof local numbers to appear trustworthy. Residents in Lowell, Lawrence, Haverhill, Fitchburg, Andover, Methuen, Gloucester, Leominster should stay alert to the following common tactics:
| Scam Type | What to Watch For |
|---|---|
| IRS / Tax Scams | Threatening calls demanding immediate tax payment via gift cards or wire transfer. |
| Utility Shut-off | Impostors claiming to be Eversource or National Grid threatening to cut power. |
| Tech Support Fraud | Pop-ups or calls claiming your computer is infected and asking for remote access. |
| Prize / Lottery Scam | Calls saying you won a prize but must pay a “fee” or “tax” to claim it. |
If you receive a suspicious call from a 351 number, take these steps to protect yourself:
- Do not share personal information such as Social Security numbers, bank details, or passwords over the phone.
- Hang up and verify by calling the organization back using an official number from its website.
- Report the call to the FTC at reportfraud.ftc.gov and to the Massachusetts Attorney General’s Office.
- Block the number and consider registering with the National Do Not Call Registry.
Red Flag: Legitimate agencies such as the IRS, Social Security Administration, or your utility company (Eversource or National Grid) will never demand immediate payment by gift card, wire transfer, or cryptocurrency. Any 351 caller making such a demand is a scammer.
Nearby & Related Area Codes
Massachusetts is served by several area codes. If you are researching 351, these neighboring and overlay codes are worth knowing:
- 978 – Merrimack Valley (overlay partner)
- 617 – Boston core
- 857 – Boston overlay
- 781 – Greater Boston suburbs
- 339 – Greater Boston overlay
You can also browse our full directory of Massachusetts area codes for more regional guides.
History and Economy of the 351 Region
The 351 area code came into service in 2001 as an overlay for the entire 978 region. Overlays were introduced across the United States as a way to add new phone numbers to a crowded area without forcing existing customers to change their established numbers. Rather than splitting the map and reassigning half the region to a new code, regulators simply layered 351 on top of 978. That means the two codes share the same cities, the same industries, and the same neighborhoods – from the former textile hubs of Lowell and Lawrence to the high-tech employers along Interstate 495 and the fishing wharves of Gloucester. When you receive a call from a 351 number, it is coming from exactly the same part of northeastern Massachusetts as a 978 call. Newer phone lines and recently activated mobile numbers in the area are especially likely to carry the 351 prefix, since it began filling in as 978 numbers grew scarce.
Looking Up a 351 Number
To identify a 351 caller, use a reverse phone lookup or search the complete 10-digit number online. Because 351 is a relatively newer code, some numbers may have less of a public footprint, so exercise extra caution and never share personal or financial details with an unverified caller.
↑ See the complete list of All US Area Codes by State – every area code across all 50 states in one directory.
Explore Neighboring States
Researching area codes just across the state line? Start with these codes in the states that border Massachusetts:
- New Hampshire – area code 603
- Vermont – area code 802
- New York – area code 212
- Connecticut – area code 203
- Rhode Island – area code 401
Frequently Asked Questions
Where is the 351 area code located?
The 351 area code serves northeastern Massachusetts as an overlay of the 978 area code, covering the Merrimack Valley, Fitchburg-Leominster, and North Shore regions.
Why does 351 cover the same area as 978?
351 is an overlay code added in 2001 because the 978 region ran short of available phone numbers. Both codes serve the exact same geographic area.
Do I have to dial 10 digits for 351?
Yes. Overlay area codes like 351 always require 10-digit dialing for local calls.
Is the 351 area code Eastern Time?
Yes, the 351 area code follows Eastern Time (EST/EDT), like all of Massachusetts.
Related 351 Guides
- Is a 351 call safe? Read Is area code 351 a scam? Spam & safety guide.
- Local coverage: see the Lowell area code guide.
- Worried about spam or robocalls? Browse our Scam Alerts directory.