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: 331 [Rate centres in NPA 331] [Dial plan for NPA 331]

NXX: 344

NPA-NXX BLOCK Rate Centre Region Switch OCN LATA LIR Eff date Disc date
331-344 A West Chicago IL   224C ONVOY, LLC 358   2026-03-26   
331-344 0 West Chicago IL   224C ONVOY, LLC 358   2026-03-26   

Last updated: Wed, 04 Mar 2026 03:00:52 UTC

Sponsored by: BeeVox - Whitelabel Reseller Platform

Like this site? We accept donations via PayPal.