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.
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NPA: 531 [Rate centres in NPA 531] [Dial plan for NPA 531]

NXX: 374

NPA-NXX BLOCK Rate Centre Region Switch OCN LATA LIR Eff date Disc date
531-374 A Valentine NE NRFLNENW9MD  6701 AERIAL COMMUNICATIONS, INC. 644   2025-05-10   
531-374 7 Valentine NE NRFLNENW9MD  5562 METROPCS, INC. 644   2025-05-12   
531-374 9 Valentine NE NRFLNENW9MD  6701 AERIAL COMMUNICATIONS, INC. 644   2025-05-10   

Last updated: Sat, 01 Aug 2026 03:19:33 UTC

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