Area Code Overview

Area code 603 is a geographic telephone area code in New Hampshire that went into service on January 1, 1947. The geographic regions covered by this area code overlay has a population of approximately 1,409,032.

Overlay and Dialing Rules

Area Code: 603
State: New Hampshire
Type: General Purpose Code
In Service Date: January 1, 1947
Overlay Complex: 603
Local Dialing Plan: This area does require you to dial the area code when calling locally.

Estimated Number of Assigned Phone Numbers in Area Code 603

This area code is ranked 184th out of 363 nationwide in estimated assigned phone numbers. Within the state territory it serves, it is ranked 1st out of 1.

4,938,000

Estimated Service-Type Mix of Assigned Phone Numbers in Area Code 603

Total assigned 4,938,000

Wireless

1,881,000 assigned

38.09%

Wireline and VoIP

1,467,000 assigned

29.71%

Other / Unclassified

1,590,000 assigned

32.20%

Estimated Share of Wireless Numbers Originally Assigned to Each Carrier in Area Code 603

Estimated assigned wireless phone numbers: 1,881,000

Numbers may later be ported to another carrier, but this chart reflects original number assignment, not current subscriber share.

Verizon Wireless 921,000 (48.96%)

T-Mobile 408,000 (21.69%)

AT&T Wireless 393,000 (20.89%)

UScellular 158,000 (8.40%)

Optimum Mobile 1,000 (0.05%)

Estimated Share of Wireline and VoIP Numbers Originally Assigned to Each Carrier in Area Code 603

Estimated assigned wireline and VoIP phone numbers: 1,467,000

PAETEC ITEL, LLC 317,000 (21.61%)

Comcast Business 241,000 (16.43%)

Onvoy 210,000 (14.31%)

Lumen 181,000 (12.34%)

TERRA NOVA TELECOM INC. 173,000 (11.79%)

Spectrum 89,000 (6.07%)

Telnyx 82,000 (5.59%)

Peerless Network 41,000 (2.79%)

MCIMETRO ACCESS TRANSMISSION SERVICES LLC - NH 40,000 (2.73%)

Bandwidth 39,000 (2.66%)

Commio 22,000 (1.50%)

Vonage 12,000 (0.82%)

Other / Unclassified Assigned Numbering in Area Code 603

Estimated assigned other or unclassified phone numbers: 1,590,000

CONSOLIDATED COMM OF NO. NEW ENGLAND-NH 1,120,000 (70.44%)

FREEDOM RING COMMUNICATIONS, LLC 147,000 (9.25%)

TELEPORT COMMUNICATIONS AMERICA, LLC - NH 81,000 (5.09%)

OTEL TELEKOM, INC. - NH 76,000 (4.78%)

IDT AMERICA, CORP. - NH 32,000 (2.01%)

GRANITE STATE TEL., INC. 30,000 (1.89%)

KEARSARGE TEL. CO. 30,000 (1.89%)

AMERICAN MESSAGING SERVICES, LLC 20,000 (1.26%)

BRETTON WOODS TEL. CO. 10,000 (0.63%)

CONSOLIDATED COMM ENTERPRISE SERVICES INC 10,000 (0.63%)

CONSOLIDATED COMMUNICATIONS OF MAINE COMPANY 10,000 (0.63%)

DUNBARTON TEL. CO. 10,000 (0.63%)

Cities and Towns in Area Code 603

Alstead, New Hampshire Alton, New Hampshire Andover, New Hampshire Antrim, New Hampshire Ashland, New Hampshire Barnstead, New Hampshire Barrington, New Hampshire Bartlett, New Hampshire Bedford, New Hampshire Belmont, New Hampshire Berlin, New Hampshire Bethlehem, New Hampshire Boscawen, New Hampshire Bradford, New Hampshire Bretton Woods, New Hampshire Bristol, New Hampshire Campton, New Hampshire Canaan, New Hampshire Candia, New Hampshire Canterbury, New Hampshire Center Harbor, New Hampshire Charlestown, New Hampshire Chatham, New Hampshire Chester, New Hampshire Chichester, New Hampshire Claremont, New Hampshire Colebrook, New Hampshire Concord, New Hampshire Contoocook, New Hampshire Conway, New Hampshire Danbury, New Hampshire Deerfield, New Hampshire Derry, New Hampshire Dover, New Hampshire Dublin, New Hampshire Dunbarton, New Hampshire Durham, New Hampshire East Conway, New Hampshire Enfield, New Hampshire Epping, New Hampshire Epsom, New Hampshire Errol, New Hampshire Exeter, New Hampshire Farmington, New Hampshire Fitzwilliam, New Hampshire Franconia, New Hampshire Franklin, New Hampshire Goffstown, New Hampshire Gorham, New Hampshire Greenfield, New Hampshire Greenville, New Hampshire Groveton, New Hampshire Hampstead, New Hampshire Hampton, New Hampshire Hancock, New Hampshire Hanover, New Hampshire Harrisville, New Hampshire Henniker, New Hampshire Hillsborough County, New Hampshire Hinsdale, New Hampshire Hollis, New Hampshire Jackson, New Hampshire Jaffrey, New Hampshire Jefferson, New Hampshire Keene, New Hampshire Kingston, New Hampshire Laconia, New Hampshire Lancaster, New Hampshire Lebanon, New Hampshire Lisbon, New Hampshire Littleton, New Hampshire Lyme, New Hampshire Madison, New Hampshire Manchester, New Hampshire Marlborough, New Hampshire Marlow, New Hampshire Melvin Village, New Hampshire Meredith, New Hampshire Meriden, New Hampshire Merrimack, New Hampshire Milan, New Hampshire Milford, New Hampshire Milton, New Hampshire Monroe, New Hampshire Nashua, New Hampshire New Boston, New Hampshire New Durham, New Hampshire New London, New Hampshire Newmarket, New Hampshire Newport, New Hampshire North Conway, New Hampshire North Stratford, New Hampshire North Walpole, New Hampshire Northwood, New Hampshire Orford, New Hampshire Pelham, New Hampshire Penacook, New Hampshire Peterborough, New Hampshire Piermont, New Hampshire Pike, New Hampshire Pittsburg, New Hampshire Pittsfield, New Hampshire Plainfield, New Hampshire Plaistow, New Hampshire Plymouth, New Hampshire Portsmouth, New Hampshire Raymond, New Hampshire Rindge, New Hampshire Rochester, New Hampshire Rumney, New Hampshire Rye Beach, New Hampshire Salem, New Hampshire Salisbury, New Hampshire Sanbornville, New Hampshire Seabrook, New Hampshire Somersworth, New Hampshire South Hampton, New Hampshire Spofford, New Hampshire Sullivan, New Hampshire Sunapee, New Hampshire Suncook, New Hampshire Sutton, New Hampshire Tamworth, New Hampshire Tilton, New Hampshire Troy, New Hampshire Walpole, New Hampshire Warner, New Hampshire Warren, New Hampshire Washington, New Hampshire Weare, New Hampshire West Chesterfield, New Hampshire West Lebanon, New Hampshire West Stewartstown, New Hampshire Westmoreland, New Hampshire Whitefield, New Hampshire Wilton, New Hampshire Winchester, New Hampshire Wolfeboro, New Hampshire Woodsville, New Hampshire

How These Figures Were Built

These figures are estimates based on public phone-number assignment records. They are meant to show the likely mix of assigned phone numbers associated with area code 603, not live customer counts.

Some providers may have assigned phone numbers tied to this area code even if they do not actively market or sell service locally. These figures reflect public number-assignment records, not confirmed local service availability.

They also do not reflect number portability at the individual phone-number level, so some numbers may now be used on a different network or by a different provider than the original assignment records suggest.

Population data and locality matching provided by GeoNames.

Last refreshed: April 15, 2026 6:22 pm