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.
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NPA: 501 [Rate centres in NPA 501] [Dial plan for NPA 501]

NXX: 578

NPA-NXX BLOCK Rate Centre Region Switch OCN LATA LIR Eff date Disc date
501-578 A Ferndale AR   348F ONVOY, LLC - AR 528   2025-05-04   
501-578 0 Ferndale AR   348F ONVOY, LLC - AR 528   2025-05-04   
501-578 1 Ferndale AR   6534 NEW CINGULAR WIRELESS PCS, LLC - IL 528   2025-07-19   

Last updated: Fri, 25 Jul 2025 03:21:23 UTC

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