Area code

NH

United States geographic area code, in service since 1947-01-01.

Statusin service

Introduced1947-01-01

JurisdictionNH, US

Local dialing10D

Time zoneEastern

Last verified2026-09-17

Utilization 97% of assignable prefixes assigned As of 09/17/2026

0%768 of ~792 assignable NXX values (200–999 excl. N11)100%

Prefix-level assignment does not equal number-level exhaustion; thousands-block pooling extends capacity. First assignment on record 2001-02-12, most recent 2024-01-23.

Area codes serve rate-center geographies, not municipal boundaries. “NH” identifies the jurisdiction, not an exact city footprint.

Top assignees

Ranked by assigned prefixes · initial assignee ≠ current carrier

Largest initial assignees in area code 603
Rank	Assignee	Prefixes	Share
01	CONSOLIDATED COMM OF NO. NEW ENGLAND-NH	247	32.2%
02	BELL ATLANTIC MOBILE, INC	74	9.6%
03	PAETEC ITEL, LLC	58	7.6%
04	MCIMETRO ACCESS TRANSMISSION SERVICES LLC - NH	44	5.7%
05	COMCAST IP PHONE, LLC	40	5.2%
06	OMNIPOINT MIAMI E LICENSE, LLC	38	4.9%
07	UNITED STATES CELLULAR - NH	37	4.8%
08	LEVEL 3 COMMUNICATIONS, LLC - NH	37	4.8%
09	NEW CINGULAR WIRELESS PCS, LLC - DC	34	4.4%
10	FREEDOM RING COMMUNICATIONS, LLC	32	4.2%

Important: these are initial assignees from NANPA CO-code records — the carrier a prefix was originally assigned to. Because of number portability, the current serving carrier of any individual number may differ.

Change history

Recorded events for this NPA

1947-01-01Area code 603 entered service.

Planning letters & orders

Primary documents

NANPA planning letters for area code 603
Date	Document	Subject
2021-01-08	PL-556 ↗	Transition to 10-digit dialing (for 988 as 3-digit access to National Suicide Prevention Lifeline) – supersedes PL-544
2020-08-17	PL-544 ↗	Transition to 10-digit dialing (for 988 as 3-digit access to National Suicide Prevention Hotline
1999-02-23	PL-163 ↗	Extraordinary NPA-Specific Jeopardy Conservation Procedures Announced for 603 NPA (New Hampshire)

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