Local Calling Guide

Area code/prefix search

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Hermosa, SD

NPA-NXX BLOCK Switch OCN LATA LIR Eff date Disc date
605-255 A HRMSSDXARS1  1660 FORT RANDALL TELCO DBA MT RUSHMORE TELEPHONE CO 640      

Last updated: Tue, 31 Mar 2026 13:56:49 UTC

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