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: 704 [Rate centres in NPA 704] [Dial plan for NPA 704]

NXX: 257

NPA-NXX BLOCK Rate Centre Region Switch OCN LATA LIR Eff date Disc date
704-257 A Denver NC   3235 LEVEL 3 COMMUNICATIONS, LLC - NC 422      
704-257 0 Denver NC   829J PAETEC ITEL, LLC 422   2001-12-22   
704-257 1 Denver NC   3235 LEVEL 3 COMMUNICATIONS, LLC - NC 422      
704-257 2 Denver NC   145J TERRA NOVA TELECOM INC. 422   2024-09-13   
704-257 3 Denver NC   3235 LEVEL 3 COMMUNICATIONS, LLC - NC 422      
704-257 4 Denver NC   3235 LEVEL 3 COMMUNICATIONS, LLC - NC 422   2004-11-13   
704-257 5 Denver NC   9412 SPRINGBOARD TELECOM, LLC - NC 422   2005-06-05   
704-257 6 Denver NC   3235 LEVEL 3 COMMUNICATIONS, LLC - NC 422   2005-11-18   
704-257 7 Denver NC   3235 LEVEL 3 COMMUNICATIONS, LLC - NC 422   2007-12-03   
704-257 8 Denver NC   3235 LEVEL 3 COMMUNICATIONS, LLC - NC 422      
704-257 9 Denver NC   515J IP HORIZON LLC 422   2026-02-20   

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

Sponsored by: ISP Telecom

Like this site? We accept donations via PayPal.