Local Calling Guide

Area code/prefix search

Search area code/prefix (NPA/NXX)
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NPA: 301 [Rate centres in NPA 301] [Dial plan for NPA 301]

NXX: 303

NPA-NXX BLOCK Rate Centre Region Switch OCN LATA LIR Eff date Disc date
301-303 A Washington Zone 13 MD SLSPMDSSX6X  6630 USA MOBILITY WIRELESS, INC. 236      

Last updated: Sat, 15 Nov 2025 03:38:44 UTC

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