New Hampshire · Eastern Time
603 Area Code
Area code 603 is in New Hampshire, serving the entire state of New Hampshire. It is in the Eastern Time zone.
Last updated October 1, 2026 · Source: NANPA
Where is the 603 area code?
603 is a New Hampshire area code covering the entire state of New Hampshire. In the wider directory it sits in the Northeast region.
Cities in the 603 area code
- Manchester
- Nashua
- Concord
- Derry
- Dover
- Rochester
- Salem
- Merrimack
- Hudson
- Londonderry
- Keene
- Portsmouth
- Laconia
- Lebanon
Counties served by 603
Hillsborough County, Rockingham County, Merrimack County, Strafford County, Cheshire County, Grafton County, Belknap County, Carroll County, Sullivan County and Coos County.
Dialing 603
Manchester, NH is currently served by the single area code 603, with no overlay. Ten-digit dialing (area code + seven-digit number) always works and is increasingly the norm nationwide; some local calls may still connect with seven digits. If a future overlay is added, 10-digit dialing would become mandatory.
From outside the US, dial +1 603 followed by the seven-digit number.
History of the 603 area code
603 is one of the original area codes assigned in 1947, when AT&T and Bell Laboratories created the North American Numbering Plan and divided the country into the first 86 numbering plan areas. It has served the Manchester area ever since.
Is 603 a scam or spam risk?
603 is a legitimate geographic area code, not a premium or toll line, so a call from it costs you nothing extra. That said, scammers frequently spoof real local area codes to look familiar on caller ID. A genuine 603 number on your screen is no guarantee the caller is in Manchester, NH or trustworthy. See spam & scam-risk area codes for how spoofing works and how to respond.
Explore more
See every code in New Hampshire, compare codes across the Northeast region, or view all Eastern Time codes. You can also browse the 6XX block or the complete numeric list of US area codes.
New to how this all works? Start with how area codes work, then read up on overlays, 10-digit dialing, and spam & scam-risk codes. To check another number, use the area code lookup tool.
Quick answers
603 area code FAQ
Where is the 603 area code?
The 603 area code is in New Hampshire, covering the entire state of New Hampshire, in the Northeast region.
What cities are in the 603 area code?
Cities in the 603 area code include Manchester, Nashua, Concord, Derry, Dover, Rochester, Salem, Merrimack, Hudson and Londonderry.
What time zone is 603 in?
603 is in the Eastern Time zone.
When did the 603 area code start?
603 went into service on January 1, 1947 as one of the original 1947 North American area codes.
Do I have to dial 10 digits for 603?
Ten-digit dialing always works, and many areas now require it; some local calls in this area may still connect with seven digits.
Is 603 a toll-free or premium code?
No. 603 is a standard geographic area code, so calling it costs the same as any local or long-distance call on your plan. Toll-free calls use 800, 888, 877, 866, 855, 844 or 833.