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: 610

NPA-NXX BLOCK Rate Centre Region Switch OCN LATA LIR Eff date Disc date
603-610 A Portsmouth NH   829J PAETEC ITEL, LLC 122   2025-04-30   
603-610 0 Portsmouth NH   829J PAETEC ITEL, LLC 122      
603-610 1 Portsmouth NH   829J PAETEC ITEL, LLC 122      
603-610 2 Portsmouth NH   829J PAETEC ITEL, LLC 122      
603-610 3 Portsmouth NH   8468 FREEDOM RING COMMUNICATIONS, LLC 122   2012-04-25   
603-610 4 Portsmouth NH   8468 FREEDOM RING COMMUNICATIONS, LLC 122   2001-12-09   
603-610 5 Portsmouth NH   8468 FREEDOM RING COMMUNICATIONS, LLC 122   2001-12-09   
603-610 6 Portsmouth NH   829J PAETEC ITEL, LLC 122      
603-610 7 Portsmouth NH   8468 FREEDOM RING COMMUNICATIONS, LLC 122   2004-04-19   
603-610 8 Portsmouth NH   8468 FREEDOM RING COMMUNICATIONS, LLC 122   2004-04-19   
603-610 9 Portsmouth NH   829J PAETEC ITEL, LLC 122      

Last updated: Thu, 29 Jan 2026 14:35:03 UTC

Sponsored by: FiberConX Communications Ltd.

Like this site? We accept donations via PayPal.