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: 227 [Rate centres in NPA 227] [Dial plan for NPA 227]

NXX: 313

NPA-NXX BLOCK Rate Centre Region Switch OCN LATA LIR Eff date Disc date
227-313 A Washington Zone 5 MD   876D ONVOY, LLC - MD 236   2026-09-28   
227-313 0 Washington Zone 5 MD   876D ONVOY, LLC - MD 236   2026-09-28   
227-313 1 Washington Zone 5 MD   071F BANDWIDTH.COM CLEC, LLC - MD 236   2026-10-16   
227-313 8 Washington Zone 5 MD   876D ONVOY, LLC - MD 236   2026-09-29   
227-313 9 Washington Zone 5 MD   876D ONVOY, LLC - MD 236   2026-09-29   

Last updated: Tue, 29 Sep 2026 03:00:13 UTC

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