Local Calling Guide

Area code/prefix search

Search area code/prefix (NPA/NXX)
  • Effective date searches are available only for US area codes. Our sources for non-US NPA-NXX data do not provide this information.
  • If you want to search an entire area code regardless of activity, leave both the next and past days fields set to zero.

NPA: 603 [Rate centres in NPA 603] [Dial plan for NPA 603]

NXX: 721

NPA-NXX BLOCK Rate Centre Region Switch OCN LATA LIR Eff date Disc date
603-721 A Milford NH MNCHNHCOCM1  5562 METROPCS, INC. 122      
603-721 0 Milford NH PTMONH073MD  8468 FREEDOM RING COMMUNICATIONS, LLC 122   2006-05-20   
603-721 1 Milford NH MNCHNHCOCM1  5562 METROPCS, INC. 122      
603-721 2 Milford NH MNCHNHCOCM1  6889 OMNIPOINT MIAMI E LICENSE, LLC 122      
603-721 3 Milford NH MNCHNHCOCM1  6889 OMNIPOINT MIAMI E LICENSE, LLC 122   2026-01-29   
603-721 4 Milford NH MNCHNHCO45Z  829J PAETEC ITEL, LLC 122   2007-03-07   
603-721 5 Milford NH MNCHNHCO43Z  792K CHARTER IP ENABLED SERVICES, LLC 122   2011-09-03   
603-721 6 Milford NH MNCHNHCOCM1  5562 METROPCS, INC. 122      
603-721 7 Milford NH MNCHNHCO44Z  829J PAETEC ITEL, LLC 122   2011-09-12   
603-721 8 Milford NH MNCHNHACAMD  6386 BELL ATLANTIC MOBILE, INC 122   2024-11-25   
603-721 9 Milford NH MNCHNHCOCM1  5562 METROPCS, INC. 122      

Last updated: Sat, 01 Aug 2026 03:19:33 UTC

Sponsored by: Callcentric - VoIP Internet phone service

Like this site? We accept donations via PayPal.