About this number
(605) 666 is a landline based telephone number operated by Fort Randall Telco DBA Mt Rush and is located in zip code 57751 in the city of Keystone, South Dakota, which is in Pennington County, and is in the Midwest. It has a Number Planning Area (NPA - also known as an Area Code) of 605 and Network Numbering Exchange (NXX - also known as a prefix) of 666. It has an Operating Company Number (OCN) of 1660. A Common Language Location Identifier (CLLI) of KYSTSDXADS1. As well as a Local access and transport area (LATA) of 640. Zip code 57751 has a population of 844 as of the 2010 census.