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: 517 [Rate centres in NPA 517] [Dial plan for NPA 517]

NXX: 223

NPA-NXX BLOCK Rate Centre Region Switch OCN LATA LIR Eff date Disc date
517-223 A Fowlerville MI FWVLMIMNRSA  9323 MICHIGAN BELL TEL CO 346      

Last updated: Thu, 20 Nov 2025 13:34:34 UTC

Sponsored by: Callcentric - VoIP Internet phone service

Like this site? We accept donations via PayPal.