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]

<< 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24

NPA-NXX BLOCK Rate Centre Region Switch OCN LATA LIR Eff date Disc date
331-999 9 Oswego IL CHCGIL24DS6  224C ONVOY, LLC 358   2019-07-14   

<< 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24

Last updated: Sat, 04 Jul 2026 13:07:56 UTC

Sponsored by: Callcentric - VoIP Internet phone service

Like this site? We accept donations via PayPal.