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: 837

NPA-NXX BLOCK Rate Centre Region Switch OCN LATA LIR Eff date Disc date
331-837 A West Chicago IL CHCGILWUTMD  516J TON80 COMMUNICATIONS, LLC 358      
331-837 0 West Chicago IL   984E BANDWIDTH.COM CLEC, LLC - IL 358   2022-08-19   
331-837 1 West Chicago IL   984E BANDWIDTH.COM CLEC, LLC - IL 358   2022-08-19   
331-837 2 West Chicago IL   6529 T-MOBILE USA, INC. 358   2022-10-24   
331-837 3 West Chicago IL   6529 T-MOBILE USA, INC. 358   2022-10-24   
331-837 4 West Chicago IL   516J TON80 COMMUNICATIONS, LLC 358   2022-03-10   
331-837 5 West Chicago IL   224C ONVOY, LLC 358   2025-04-06   
331-837 6 West Chicago IL   321J HD CARRIER LLC 358   2025-10-10   
331-837 7 West Chicago IL   224C ONVOY, LLC 358   2024-03-01   
331-837 8 West Chicago IL   224C ONVOY, LLC 358   2023-07-22   
331-837 9 West Chicago IL   224C ONVOY, LLC 358   2024-03-01   

Last updated: Thu, 29 Jan 2026 14:35:03 UTC

Sponsored by: VoIP.ms

Like this site? We accept donations via PayPal.