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: 451

NPA-NXX BLOCK Rate Centre Region Switch OCN LATA LIR Eff date Disc date
307-451 A Rock Springs WY CHYNWYRF5MD  197D VONAGE AMERICA LLC 654   2024-06-27   
307-451 0 Rock Springs WY   450F ONVOY, LLC - WY 654   2025-05-10   
307-451 9 Rock Springs WY CHYNWYRF5MD  197D VONAGE AMERICA LLC 654   2024-06-27   

Last updated: Wed, 18 Jun 2025 02:30:00 UTC

Sponsored by: Execulink Telecom

Like this site? We accept donations via PayPal.