Local Calling Guide

Area code/prefix search

Search area code/prefix (NPA/NXX)
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Washington Zone 15, MD

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NPA-NXX BLOCK Switch OCN LATA LIR Eff date Disc date
301-358 6   6119 LEVEL 3 COMMUNICATIONS, LLC - MD 236   2006-09-29   
301-358 7   2593 CORE COMMUNICATIONS, INC.- MD 236   2019-04-29   
301-358 8   624H ONVOY SPECTRUM, LLC 236   2021-11-08   
301-358 9   6119 LEVEL 3 COMMUNICATIONS, LLC - MD 236      
301-574 A MRBOMDMBDS0  9212 VERIZON MARYLAND, INC. 236      
301-574 0   9212 VERIZON MARYLAND, INC. 236      
301-574 1   9212 VERIZON MARYLAND, INC. 236      
301-574 2   9212 VERIZON MARYLAND, INC. 236      
301-574 3   9212 VERIZON MARYLAND, INC. 236      
301-574 4   9212 VERIZON MARYLAND, INC. 236      
301-574 5   9212 VERIZON MARYLAND, INC. 236      
301-574 6   2593 CORE COMMUNICATIONS, INC.- MD 236   2019-04-29   
301-574 7   318J COMCAST IP PHONE, LLC 236   2018-11-29   
301-574 8   9212 VERIZON MARYLAND, INC. 236      
301-574 9   9212 VERIZON MARYLAND, INC. 236      
301-627 A MRBOMDMBDS0  9212 VERIZON MARYLAND, INC. 236      
301-715 A WASHDCTTDS0  7529 TELEPORT COMMUNICATIONS AMERICA, LLC - DC 236      
301-715 0   515J IP HORIZON LLC 236   2019-04-26   
301-715 1   2593 CORE COMMUNICATIONS, INC.- MD 236   2018-06-16   
301-715 2   7529 TELEPORT COMMUNICATIONS AMERICA, LLC - DC 236      
301-715 3   6119 LEVEL 3 COMMUNICATIONS, LLC - MD 236   2009-10-09   
301-715 4   2593 CORE COMMUNICATIONS, INC.- MD 236   2018-06-16   
301-715 5   2593 CORE COMMUNICATIONS, INC.- MD 236   2018-06-16   
301-715 6   624H ONVOY SPECTRUM, LLC 236   2021-11-08   
301-715 7   624H ONVOY SPECTRUM, LLC 236   2022-06-14   
301-715 8   568G PEERLESS NETWORK OF MARYLAND, LLC 236   2016-11-19   
301-715 9   515J IP HORIZON LLC 236   2019-04-26   
301-780 A MRBOMDMBDS0  9212 VERIZON MARYLAND, INC. 236      
301-780 0   9212 VERIZON MARYLAND, INC. 236      
301-780 1   9212 VERIZON MARYLAND, INC. 236      
301-780 2   9212 VERIZON MARYLAND, INC. 236      
301-780 3   9212 VERIZON MARYLAND, INC. 236      
301-780 4   876D ONVOY, LLC - MD 236   2017-07-12   
301-780 5   9212 VERIZON MARYLAND, INC. 236      
301-780 6   9212 VERIZON MARYLAND, INC. 236      
301-780 7   9212 VERIZON MARYLAND, INC. 236      
301-780 8   9212 VERIZON MARYLAND, INC. 236      
301-780 9   9212 VERIZON MARYLAND, INC. 236      
301-952 A MRBOMDMBDS0  9212 VERIZON MARYLAND, INC. 236      

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

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