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: 521

NPA-NXX BLOCK Rate Centre Region Switch OCN LATA LIR Eff date Disc date
603-521 A Nashua NH MNCHNHCOA02  7421 AT&T - LOCAL 122      
603-521 0 Nashua NH DRRYNHBC1MD  4036 NEW CINGULAR WIRELESS PCS, LLC - DC 122   2006-09-01   
603-521 1 Nashua NH MNCHNHCOA02  7421 AT&T - LOCAL 122      
603-521 2 Nashua NH MNCHNHACAMD  6386 BELL ATLANTIC MOBILE, INC 122   2007-02-02   
603-521 3 Nashua NH MNCHNHCOA02  7421 AT&T - LOCAL 122      
603-521 4 Nashua NH MNCHNHACAMD  6386 BELL ATLANTIC MOBILE, INC 122   2006-04-01   
603-521 5 Nashua NH MNCHNHACAMD  6386 BELL ATLANTIC MOBILE, INC 122   2006-04-01   
603-521 6 Nashua NH   829J PAETEC ITEL, LLC 122   2006-04-29   
603-521 7 Nashua NH MNCHNHIE6MD  318J COMCAST IP PHONE, LLC 122   2006-04-07   
603-521 8 Nashua NH MNCHNHIE6MD  318J COMCAST IP PHONE, LLC 122   2006-04-07   
603-521 9 Nashua NH MNCHNHCOA02  7421 AT&T - LOCAL 122      

Last updated: Sat, 05 Apr 2025 03:03:23 UTC

Sponsored by: ISP Telecom

Like this site? We accept donations via PayPal.