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.

NPA: 307 [Rate centres in NPA 307] [Dial plan for NPA 307]

NXX: 428

NPA-NXX BLOCK Rate Centre Region Switch OCN LATA LIR Eff date Disc date
307-428 A Douglas WY CSPRWYMAXEX  6529 T-MOBILE USA, INC. 654   2024-02-03   
307-428 0 Douglas WY CHYNWYMAX2X  450F ONVOY, LLC - WY 654   2024-03-07   
307-428 1 Douglas WY CHYNWYMAX2X  450F ONVOY, LLC - WY 654   2024-07-06   
307-428 2 Douglas WY   450F ONVOY, LLC - WY 654   2025-03-01   
307-428 3 Douglas WY   6566 CELLCO PARTNERSHIP DBA VERIZON WIRELESS - WY 654   2025-04-03   
307-428 9 Douglas WY CSPRWYMAXEX  6529 T-MOBILE USA, INC. 654   2024-02-03   

Last updated: Sat, 05 Apr 2025 03:03:23 UTC

Sponsored by: Execulink Telecom

Like this site? We accept donations via PayPal.