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: 734 [Rate centres in NPA 734] [Dial plan for NPA 734]

NXX: 240

NPA-NXX BLOCK Rate Centre Region Switch OCN LATA LIR Eff date Disc date
734-240 A Monroe MI MONRMIMNDS0  9323 MICHIGAN BELL TEL CO 340      

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

Sponsored by: ISP Telecom

Like this site? We accept donations via PayPal.