Local Calling Guide

Area code/prefix search

Search area code/prefix (NPA/NXX)
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NPA: 571 [Rate centres in NPA 571] [Dial plan for NPA 571]

NXX: 743

NPA-NXX BLOCK Rate Centre Region Switch OCN LATA LIR Eff date Disc date
571-743 A Herndon VA   138E ONVOY, LLC - VA 236   2025-12-26   
571-743 0 Herndon VA   138E ONVOY, LLC - VA 236   2025-12-26   
571-743 1 Herndon VA   138E ONVOY, LLC - VA 236   2026-02-20   
571-743 8 Herndon VA   138E ONVOY, LLC - VA 236   2026-01-10   
571-743 9 Herndon VA   138E ONVOY, LLC - VA 236   2026-01-10   

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

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