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: 303 [Rate centres in NPA 303] [Dial plan for NPA 303]

NXX: 645

NPA-NXX BLOCK Rate Centre Region Switch OCN LATA LIR Eff date Disc date
303-645 A Denver CO ENWDCOABDS0  9636 QWEST CORPORATION 656      
303-645 0 Denver CO   9636 QWEST CORPORATION 656      
303-645 1 Denver CO   9636 QWEST CORPORATION 656      
303-645 2 Denver CO   9636 QWEST CORPORATION 656      
303-645 3 Denver CO   508J CENTURYLINK COMMUNICATIONS, LLC 656   2016-04-17   
303-645 4 Denver CO   3467 ELECTRIC LIGHTWAVE LLC DBA ALLSTREAM 656   2006-09-14   
303-645 5 Denver CO   9636 QWEST CORPORATION 656      
303-645 6 Denver CO   9636 QWEST CORPORATION 656      
303-645 7 Denver CO   9636 QWEST CORPORATION 656      
303-645 8 Denver CO   9636 QWEST CORPORATION 656      
303-645 9 Denver CO   9636 QWEST CORPORATION 656      

Last updated: Tue, 13 Jan 2026 21:50:02 UTC

Sponsored by: VoIP Much Phone Company

Like this site? We accept donations via PayPal.