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.
  • If you want to search an entire area code regardless of activity, leave both the next and past days fields set to zero.

Switch: GRFLMTTH1MD

NPA-NXX BLOCK Rate Centre Region OCN LATA LIR Eff date Disc date
406-221 9 Butte MT 520K TDS METROCOM, LLC 648   2025-11-17   
406-268 5 Great Falls MT 520K TDS METROCOM, LLC 648   2025-11-17   
406-440 7 Helena MT 520K TDS METROCOM, LLC 648   2025-11-17   
406-618 A Missoula MT 520K TDS METROCOM, LLC 648   2025-12-05   
406-618 2 Missoula MT 520K TDS METROCOM, LLC 648   2025-12-05   

Last updated: Thu, 16 Jul 2026 02:21:55 UTC

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