Reference Data Rate Center Directory EUREKA, SD Rate Center EUREKA — SD Data last updated: March 10, 2026 LATA 640 State SD Area Codes 1 Exchanges (NXX) 1 Carriers 1 Coordinates 45.76901528335785, -99.6203696550983 Area Codes 605 Top Carriers Carrier OCN NXX Count VALLEY TELECOM COOP. ASSN., INC. 1685 1
