The 603 area code is the single area code serving the entire state of New Hampshire, from Manchester and Nashua in the south to the White Mountains and the North Country. One of the original area codes assigned in 1947, 603 has covered all of New Hampshire on its own ever since and has become a proud symbol of Granite State identity.
Quick Summary of the 603 Area Code
| Area Code | 603 |
| State | New Hampshire (NH) |
| Region | Statewide New Hampshire |
| Major Cities | Manchester, Nashua, Concord, Derry, Dover, Rochester, Salem, Portsmouth |
| Time Zone | Eastern Time (ET) – EST / EDT |
| Dialing Format | 7 or 10-digit dialing |
Geographic Coverage
The 603 area code is a statewide code covering all of New Hampshire, including the largest city of Manchester and its neighbor Nashua in the south, the state capital of Concord, the fast-growing towns of Derry and Salem near the Massachusetts line, the Seacoast cities of Portsmouth, Dover, and Rochester, and the college towns of Durham and Hanover. It borders Massachusetts, Maine, Vermont, and the Canadian province of Quebec.
Time Zone
The 603 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. All of New Hampshire is on Eastern Time, the same as neighboring Massachusetts and Maine. From the West Coast, this region is three hours ahead of Pacific Time, so a 9:00 AM call in California reaches a 603 number at 12:00 PM local time.
Tip: Business hours across the 603 region generally run 9:00 AM to 5:00 PM Eastern Time, Monday through Friday.
How to Dial a 603 Number
Area code 603 is not part of an overlay, and as the only area code in New Hampshire it has traditionally allowed 7-digit local dialing within the state. However, 10-digit dialing is now the recommended nationwide standard, and dialing the full 10-digit number (603 + the seven-digit line number) always works reliably. For international callers, dial your country’s exit code, then +1 (the North American country code), then 603, followed by the seven-digit local number.
Scam Alerts for the 603 Area Code
Like every U.S. area code, 603 has been used by scammers who spoof local numbers to appear trustworthy. Residents in Manchester, Nashua, Concord, Derry, Dover, Rochester, Salem, Portsmouth should stay alert to the following common tactics:
| Scam Type | What to Watch For |
|---|---|
| IRS / Tax Scams | Callers claiming you owe back taxes and threatening arrest unless you pay immediately. |
| Utility Shut-off | Fake Eversource or Unitil reps demanding payment to avoid disconnection in winter. |
| Storm / Heating Scam | Fake contractors or fuel dealers demanding upfront payment for winter storm repairs or heating oil. |
| Bank Fraud Alerts | Robocalls impersonating your bank about “suspicious activity” to phish account details. |
If you receive a suspicious call from a 603 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 New Hampshire Consumer Protection Bureau.
- 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 local utility company (Eversource or Unitil) will never demand immediate payment by gift card, wire transfer, or cryptocurrency. Any 603 caller making such a demand is a scammer.
History and Economy of the 603 Region
n
Area code 603 is one of the original 86 codes established in 1947, and it remains one of the last single-area-code states in the country – New Hampshire has never needed an overlay or a split. The “603” has become a strong emblem of local pride, appearing on apparel, businesses, and the state’s “Live Free or Die” culture. The regional economy is anchored by Manchester and Nashua in the south, a technology and manufacturing corridor closely tied to the Greater Boston economy and boosted by New Hampshire’s lack of a state sales or income tax. The Seacoast around Portsmouth blends tourism, a working port, and the Portsmouth Naval Shipyard, while the University of New Hampshire in Durham and Dartmouth College in Hanover drive education and research. Tourism is a year-round pillar, drawing visitors to the White Mountains, Lake Winnipesaukee, ski resorts, and the famous New England fall foliage.
n
Looking Up a 603 Number
n
To identify a 603 caller, use a reverse phone lookup service or search the full 10-digit number online. Many New Hampshire businesses, government offices, and healthcare providers list their 603 numbers publicly, so a quick search often confirms a legitimate caller. For unknown numbers, let the call go to voicemail – genuine callers usually leave a message, while robocallers and scammers rarely do.
Nearby & Related Area Codes
New Hampshire is served by the single 603 area code, with no overlay. These neighboring New England codes are worth knowing:
You can also browse our full directory of New Hampshire area codes for more regional guides.
↑ 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 New Hampshire:
Frequently Asked Questions
Where is the 603 area code located?
The 603 area code covers the entire state of New Hampshire, including Manchester, Nashua, Concord, Derry, Dover, Rochester, Salem, and Portsmouth.
Does New Hampshire have more than one area code?
No. New Hampshire is served entirely by the single 603 area code, one of the few states in the country still covered by just one code with no overlay.
Do I need to dial 10 digits for 603?
As the only area code in New Hampshire, 603 has historically allowed 7-digit local dialing, but dialing the full 10 digits is now the recommended standard and always works.
What time zone is the 603 area code in?
The 603 area code is in the Eastern Time Zone (EST/EDT), the same as neighboring Massachusetts, Maine, and Vermont.
Related 603 Guides
- Is a 603 call safe? Read Is area code 603 a scam? Spam & safety guide.
- Local coverage: see the Manchester area code guide.
- Worried about spam or robocalls? Browse our Scam Alerts directory.