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.
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Rock River, WY

NPA-NXX BLOCK Switch OCN LATA LIR Eff date Disc date
307-378 A RCRVWYXCRS1  2297 UNION TEL. CO. 654      
307-798 A CHYNWYVACM1  013B UNION TELEPHONE COMPANY 654      

Last updated: Sun, 07 Dec 2025 22:02:11 UTC

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