Area code
603
603 is a United States area code. Under the North American Numbering Plan it belongs to New Hampshire, which has 1 area code in total.
Validate a number in 603
Paste a full number and the tool checks it against the numbering plan. It returns the standard formats, the line type the plan assigns and the area code region.
Digits with or without punctuation work. Numbers outside the US are read with the +country code.
Area code 603 at a glance
NANPA lists 752 central office codes (prefixes) in use in area code 603, held by 48 holders across 147 rate centers.
| Fact | Value |
|---|---|
| In service since | 1947-01-01 |
| Time zone | Eastern (E) |
| Prefixes in use | 752 |
| Pooled prefixes | 602 (80%) |
| Rate centers | 147 |
| Companies holding prefixes | 48 |
| Assignment dates on file | 2001-02-12 to 2024-01-23 (171 prefixes) |
| ZIP codes in its places | 143 |
Rate centers in area code 603
| Rate center | Prefixes | Share |
|---|---|---|
| MANCHESTER | 80 | 11% |
| NASHUA | 58 | 8% |
| CONCORD | 39 | 5% |
| DERRY | 29 | 4% |
| DOVER | 29 | 4% |
| PORTSMOUTH | 28 | 4% |
| MERRIMACK | 23 | 3% |
| SALEM | 20 | 3% |
| 139 other rate centers | 446 | 59% |
Who holds the prefixes in 603
Consolidated Comm Of No. New England-Nh holds the most prefixes, 246 (33%). 80% of the prefixes are pooled, which means their thousands-blocks can belong to different companies.
| Holder | Prefixes | Share |
|---|---|---|
| Consolidated Comm Of No. New England-Nh | 246 | 33% |
| Bell Atlantic Mobile | 74 | 10% |
| Paetec Itel | 58 | 8% |
| Mcimetro Access Transmission Services | 45 | 6% |
| Comcast IP Phone | 40 | 5% |
| Omnipoint Miami E License | 38 | 5% |
| 42 other carriers | 251 | 33% |
A prefix holder is the company a code was assigned to, not necessarily a number's current carrier, because numbers can be ported to another company. Find which carrier a number is on, or browse the prefix holders.
History of area code 603
- 1947-01-01 Area code 603 went into service.
Area codes nearest to 603
Distance is measured between the centers of the ZIP code places each area code serves, so it is a rough guide.
ZIP codes in area code 603
143 ZIP codes fall in places that have a rate center in this area code.
| Place | ZIP codes |
|---|---|
| Manchester, NH | 8 |
| Nashua, NH | 5 |
| Concord, NH | 4 |
A ZIP code and an area code are unrelated systems. A ZIP code can sit in more than one area code, and an area code spans many ZIP codes.
Complaints on file for 603 numbers
2,754 FCC complaints are on file for 2,234 numbers in 603, most often filed as "Unwanted Calls". These are unverified consumer reports.
| Year of latest complaint | Numbers |
|---|---|
| 2023 | 155 |
| 2024 | 121 |
| 2025 | 131 |
New Hampshire has one area code
603 is the only area code the table assigns to New Hampshire, so every geographic number there starts with it.
Next to 603 in the numbering table
These are the codes just before and after 603 when all are sorted by number. They are neighbours on the list, not necessarily on the map.
What the area code does and does not tell you
A number that starts with 603 was first assigned in New Hampshire. That is a fact about where the number began, and it is a useful hint when you check a form entry, for example a billing address in New Hampshire next to a 603 phone number.
It does not show where the person is today. A number stays with its owner after a move or a change of provider (number portability), and mobile numbers travel with the handset. The area code also cannot tell you whether the line is active, who the carrier is, or whether the number is mobile or fixed: the plan shares those ranges. Read more about the area code, the numbering plan and line type.
Check numbers in bulk with the API
| Product | Credits | Docs |
|---|---|---|
| Phone Numbering-Plan Validation | 1 credit per valid number | API docs |
| Phone Intelligence (carrier and line status) | 1 credit per check (invalid numbers outside the US and Canada are free) | Product page |
Questions about area code 603
Where is area code 603?
NANPA assigns area code 603 to New Hampshire, United States.
In which state does area code 603 sit?
New Hampshire. 603 is one of 1 area code the NANPA table assigns to the state.
Which places does area code 603 cover?
The places with the most ZIP codes among the rate centers in 603 are Manchester, NH, Nashua, NH and Concord, NH. The rate center list on this page shows all of them.
Who owns area code 603?
NANPA assigns area codes. Within 603, Consolidated Comm Of No. New England-Nh holds the most prefixes, 246 prefixes or 33%.
Which time zone does 603 use?
The NANPA NPA report lists the time zone for 603 as Eastern (E).
What year did 603 enter service?
The NANPA NPA report gives an in-service date of 1947-01-01, so 603 has been in use since 1947.
Does area code 603 have an overlay?
The NANPA NPA report lists no other area code in an overlay with 603.
Which area codes are nearest to 603?
The area codes closest to 603, measured between the centers of the ZIP code places they serve, are 351 (about 53 miles), 978 (about 54 miles), 617 (about 75 miles), 802 (about 75 miles) and 857 (about 75 miles).
How many prefixes does area code 603 have?
NANPA's report dated 2026-10-17 lists 752 prefixes in service in 603, spread over 147 rate centers and 48 holders.
Are there complaints about 603 numbers?
The FCC data on file has 2,754 complaints for 2,234 numbers in 603. They are unverified consumer reports. A number with no complaints on file is not proven safe.
Area code assignments: North American Numbering Plan Administrator NPA report, file dated 10/17/2026, retrieved 2026-10-17. Source file. New codes are assigned several times a year. Prefixes, rate centers, holders, time zone, in-service date and overlays: NANPA central office code report dated 2026-10-17 and NPA report dated 2026-10-18. Complaints: FCC consumer complaints open data, fetched 2026-10-17. ZIP code places: Postal code places and coordinates: GeoNames (geonames.org), licensed CC BY 4.0.