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.

Grass Range, MT

NPA-NXX BLOCK Switch OCN LATA LIR Eff date Disc date
406-428 A RNDPMTXCDS0  2246 MID-RIVERS TEL. COOP., INC. 650      
406-428 2   2246 MID-RIVERS TEL. COOP., INC. 650      
406-428 8   6564 CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MT 650   2018-12-17   
406-928 A BLNGMTWEIMD  6564 CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MT 650      
406-928 0   6564 CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MT 650      
406-928 8   6564 CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MT 650      
406-928 9   6564 CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MT 650      

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

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