Local Calling Guide

Area code/prefix search

Search area code/prefix (NPA/NXX)
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NPA: 410 [Rate centres in NPA 410] [Dial plan for NPA 410]

NXX: 623

NPA-NXX BLOCK Rate Centre Region Switch OCN LATA LIR Eff date Disc date
410-623 A Marion MD MARNMDMARS1  9212 VERIZON MARYLAND, INC. 242      
410-623 0 Marion MD   2593 CORE COMMUNICATIONS, INC.- MD 242   2004-04-03   
410-623 1 Marion MD   145J TERRA NOVA TELECOM INC. 242   2024-02-14   
410-623 2 Marion MD   9212 VERIZON MARYLAND, INC. 242      
410-623 3 Marion MD   876D ONVOY, LLC - MD 242   2019-03-04   
410-623 4 Marion MD   145J TERRA NOVA TELECOM INC. 242   2025-05-07   
410-623 5 Marion MD   073H TELNYX LLC 242   2017-09-13   
410-623 6 Marion MD   145J TERRA NOVA TELECOM INC. 242   2024-09-13   
410-623 7 Marion MD   876D ONVOY, LLC - MD 242   2017-04-14   
410-623 8 Marion MD   9212 VERIZON MARYLAND, INC. 242      
410-623 9 Marion MD   792K CHARTER IP ENABLED SERVICES, LLC 242   2020-09-25   

Last updated: Tue, 13 Jan 2026 21:50:02 UTC

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