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.

Roundup, MT

NPA-NXX BLOCK Switch OCN LATA LIR Eff date Disc date
406-320 A BLNGMTWEIMD  6564 CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MT 650      
406-320 0 BLNGMTWEIMD  6564 CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MT 650      
406-320 1 BLNGMTWEIMD  6564 CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MT 650      
406-320 2 BLNGMTWEIMD  6564 CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MT 650      
406-320 3 BLNGMTWE6MD  9415 LEVEL 3 COMMUNICATIONS, LLC - MT 650   2019-10-10   
406-323 A RNDPMTXCDS0  2246 MID-RIVERS TEL. COOP., INC. 650      
406-323 1 RNDPMTXCDS0  2246 MID-RIVERS TEL. COOP., INC. 650      
406-323 2 RNDPMTXCDS0  2246 MID-RIVERS TEL. COOP., INC. 650      
406-323 3 RNDPMTXCDS0  2246 MID-RIVERS TEL. COOP., INC. 650      
406-323 4 RNDPMTXCDS0  2246 MID-RIVERS TEL. COOP., INC. 650      
406-323 7 RNDPMTXCDS0  2246 MID-RIVERS TEL. COOP., INC. 650      
406-323 8 RNDPMTXCDS0  2246 MID-RIVERS TEL. COOP., INC. 650      
406-323 9 RNDPMTXCDS0  2246 MID-RIVERS TEL. COOP., INC. 650      
406-331 A BLNGMTWEIMD  6564 CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MT 650      
406-331 0 BLNGMTWEIMD  6564 CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MT 650      
406-331 1   145J TERRA NOVA TELECOM INC. 650   2025-08-29   
406-913 A BLNGMTWEIMD  6564 CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MT 650      
406-913 0 BLNGMTWEIMD  6564 CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MT 650      
406-913 9 BLNGMTWEIMD  6564 CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MT 650      

Last updated: Thu, 16 Oct 2025 03:04:18 UTC

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