--- title: "Area code 603: New Hampshire, United States" url: "https://lookvalid.com/area-code/603.md" canonical_url: "https://lookvalid.com/area-code/603" last_updated: "2026-10-23" type: "reference" summary: "Area code 603 serves New Hampshire, United States. Number formats, numbering rules, a live phone validator and the other codes in New Hampshire." --- # Area code 603: New Hampshire, United States Area code 603 serves New Hampshire, United States. Number formats, numbering rules, a live phone validator and the other codes in New Hampshire. NANPA lists 752 central office codes (prefixes) in use in area code 603, held by 48 holders across 147 rate centers. 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. The FCC unwanted-call data has 2,754 complaints on file for 2,234 numbers in 603, most often filed as "Unwanted Calls". These are consumer reports, not findings. ## Facts - 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 | 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% | ## Carriers | 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. ## History - 1947-01-01: Area code 603 went into service. ## Nearest area codes 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). ## ZIP codes 143 ZIP codes fall in places that have a rate center in this area code. The places with the most are Manchester, NH (8 ZIP codes), Nashua, NH (5 ZIP codes) and Concord, NH (4 ZIP codes). A ZIP code and an area code are unrelated systems, so a ZIP code can sit in more than one area code and an area code spans many ZIP codes. ## Complaints on file 2,754 complaints for 2,234 numbers. Numbers whose latest complaint falls in each year: - 2023: 155 - 2024: 121 - 2025: 131 ## Questions ### 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. Sources: NANPA central office code report dated 2026-10-17; NANPA NPA report dated 2026-10-18; FCC unwanted-call complaints, data fetched 2026-10-17; ZIP code places from GeoNames (CC BY 4.0).