Reference Data Rate Center Directory SO GUELPH, SD Rate Center SO GUELPH — SD Data last updated: March 10, 2026 LATA 636 State SD Area Codes 1 Exchanges (NXX) 1 Carriers 1 Coordinates 45.91585020649396, -98.363743412358 Area Codes 605 Top Carriers Carrier OCN NXX Count DICKEY RURAL TEL. COOP. 1611 1
