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: 231 [Rate centres in NPA 231] [Dial plan for NPA 231]

NXX: 937

NPA-NXX BLOCK Rate Centre Region Switch OCN LATA LIR Eff date Disc date
231-937 A Howard City MI HWCYMIXGDS0  0695 FRONTIER NORTH, INC. - MI 348      
231-937 0 Howard City MI GDRPMIBLXTZ  3535 ACD TELECOM, INC. - MI 348   2005-02-11   
231-937 1 Howard City MI MSKGMIXKFMD  691A DAYSTARR, LLC DBA DAYSTARR COMMUNICATIONS - MI 348   2014-07-15   
231-937 2 Howard City MI GDRPMIQLX5Y  6120 LEVEL 3 COMMUNICATIONS, LLC - MI 348   2004-07-17   
231-937 3 Howard City MI   145J TERRA NOVA TELECOM INC. 348   2025-07-12   
231-937 4 Howard City MI HWCYMIXGDS0  0695 FRONTIER NORTH, INC. - MI 348      
231-937 5 Howard City MI HWCYMIXGDS0  0695 FRONTIER NORTH, INC. - MI 348      
231-937 6 Howard City MI HWCYMIXGDS0  0695 FRONTIER NORTH, INC. - MI 348      
231-937 7 Howard City MI HWCYMIXGDS0  0695 FRONTIER NORTH, INC. - MI 348      
231-937 8 Howard City MI HWCYMIXGDS0  0695 FRONTIER NORTH, INC. - MI 348      
231-937 9 Howard City MI HWCYMIXGDS0  0695 FRONTIER NORTH, INC. - MI 348      

Last updated: Thu, 16 Oct 2025 03:04:18 UTC

Sponsored by: FiberConX Communications Ltd.

Like this site? We accept donations via PayPal.