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-NXX BLOCK Rate Centre Region OCN LATA LIR Eff date Disc date
636-630 A O'Fallon MO 939H COMMIO, LLC 520      
636-630 0 O'Fallon MO 939H COMMIO, LLC 520   2022-07-21   

Last updated: Thu, 16 Oct 2025 03:04:18 UTC

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