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.

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NPA-NXX BLOCK Rate Centre Region OCN LATA LIR Eff date Disc date
303-637 A Denver CO 9636 QWEST CORPORATION 656      
303-654 A Denver CO 9636 QWEST CORPORATION 656      
303-655 A Denver CO 9636 QWEST CORPORATION 656      
303-659 A Denver CO 9636 QWEST CORPORATION 656      
720-523 A Denver CO 9636 QWEST CORPORATION 656      
720-685 A Denver CO 9636 QWEST CORPORATION 656      

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

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