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US area code · New Hampshire

Area code 603

Where the 603 area code is, its overlay and how to dial a +1 603 number from anywhere.

CoversEast Concord, New HampshireTime zoneEastern (ET)TypeGeographic
Quick answer

The 603 area code is in East Concord, New Hampshire, United States (Eastern (ET)). To call from abroad: +1 603 555-0123.

StateNew Hampshire
Main areaEast Concord
Time zoneEastern (ET)
TypeGeographic
10-digit dialingRequired
In service since01-Jan-1947

The 603 area code is a geographic North American Numbering Plan (NANP) code covering East Concord, New Hampshire. It has been in service since 01-Jan-1947 and sits in the Eastern (ET) time zone.

How to dial a 603 number

From abroad+1 603 555-0123
Within the US / Canada1 603 555-0123
Locally (same area)603 555-0123

Cities in the 603 area code

A 603 number is usually in one of these places in New Hampshire — 4 counties.

Derry RockinghamDover StraffordEast ConcordKeene CheshireManchester HillsboroughNashua HillsboroughPortsmouth RockinghamRochester Strafford

Frequently asked questions

Where is the 603 area code?

The 603 area code is in East Concord, New Hampshire, United States (Eastern (ET)).

Do I have to dial 10 digits for 603?

Yes — dial the area code plus the seven-digit number.

How do I call a 603 number from another country?

Dial your exit code (or +), then 1, then 603, then the number: +1 603 555-0123.

Source: NANPA numbering plan. An area code covers a region, not a precise address — a 603 number does not pinpoint a street or ZIP code.

Missed a call from +1 603?

In the 30 days to September 24, 2026, 399 unwanted calls showing a 603 number were reported to the US Federal Trade Commission, 57% of them recorded messages or robocalls. That puts 603 at #244 of 670 area codes reported.

Other174
Dropped call or no message52
Calls pretending to be government, businesses, or family and friends43
Reducing your debt (credit cards, mortgage, student loans)27
Before you call back
  • If you do not know anyone in New Hampshire, do not call back: a genuine caller will leave a message or send a text.
  • Scammers fake the number shown on caller ID, so a 603 number can hide a caller anywhere in the world.
  • Never give a code received by text or a bank detail to an unknown caller. In the US, calls can be reported at reportfraud.ftc.gov.

Who issues +1 603 numbers

Phone companies hold blocks of numbers in each area code. The main holders in 603:

Consolidated Comm Of No. New England-Nh 247Bell Atlantic Mobile, Inc 74Paetec Itel, LLC 58Mcimetro Access Transmission Services LLC 44Comcast Ip Phone, LLC 40Omnipoint Miami E License, LLC 38

About 4.6% of the 768 prefixes in use belong to mobile carriers: a 603 number is often a cell phone, and it may have moved to another carrier since.

Sources: FTC Do Not Call reported calls (numbers as reported by consumers, not verified), NANPA central office code assignments.

All US area codes United States +1 Map of area code 603 — cities & rate centres