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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Switch: CLPKMTMARS1

NPA-NXX BLOCK Rate Centre Region OCN LATA LIR Eff date Disc date
406-686 A Clyde Park MT 9636 QWEST CORPORATION 650      

Last updated: Tue, 13 Jan 2026 21:50:02 UTC

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