Reference Data Rate Center Directory CHESTER, SD Rate Center CHESTER — SD Data last updated: March 10, 2026 LATA 640 State SD Area Codes 1 Exchanges (NXX) 1 Carriers 1 Coordinates 43.89507262703788, -96.92737328895336 Area Codes 605 Top Carriers Carrier OCN NXX Count INTERSTATE TELECOM COOP, INC. - SD 1651 1
