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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Waterloo, MD

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NPA-NXX BLOCK Switch OCN LATA LIR Eff date Disc date
667-374 7 BLTMMDCH42Z  876D ONVOY, LLC - MD 238   2022-09-25   
667-374 8 BLTMMDCHXUX  624H ONVOY SPECTRUM, LLC 238   2022-02-11   
667-374 9 BLTMMDCHXUX  624H ONVOY SPECTRUM, LLC 238   2022-02-11   

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Last updated: Thu, 05 Feb 2026 23:41:55 UTC

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