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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OCN: 958H TRIANGLE COMMUNICATION SYSTEM, INC. - MT-

NPA-NXX BLOCK Rate Centre Region Switch LATA LIR Eff date Disc date
406-399 8 South Havre MT HAVRMTXCDS1  648   2017-07-01   
406-400 A Havre MT HAVRMTXCDS1  648      
406-400 2 Havre MT HAVRMTXCDS1  648   2017-06-18   

Last updated: Sun, 26 Jan 2025 15:59:20 UTC

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