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: 557 [Rate centres in NPA 557] [Dial plan for NPA 557]

NXX: 241

NPA-NXX BLOCK Rate Centre Region Switch OCN LATA LIR Eff date Disc date
557-241 A Ladue MO   093F ONVOY, LLC - MO 520   2025-11-15   
557-241 0 Ladue MO   093F ONVOY, LLC - MO 520   2025-11-15   
557-241 1 Ladue MO   093F ONVOY, LLC - MO 520   2025-11-15   
557-241 2 Ladue MO   093F ONVOY, LLC - MO 520   2025-11-15   
557-241 3 Ladue MO   093F ONVOY, LLC - MO 520   2025-11-15   
557-241 4 Ladue MO   093F ONVOY, LLC - MO 520   2025-11-15   
557-241 5 Ladue MO   5814 CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MO 520   2026-01-31   
557-241 6 Ladue MO   5814 CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MO 520   2026-02-05   
557-241 7 Ladue MO   5814 CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MO 520   2026-02-05   
557-241 8 Ladue MO   093F ONVOY, LLC - MO 520   2025-11-17   
557-241 9 Ladue MO   093F ONVOY, LLC - MO 520   2025-11-17   

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

Sponsored by: VoIP Much Phone Company

Like this site? We accept donations via PayPal.