What are the Foster, South Dakota Zip Codes for 2020, 2019Primary Zip Codes for FosterZip CodePrimary CitySecondary City57601MobridgeFoster, Gopher, PromiseCities sharing Zip Codes with FosterZip CodePrimary CitySecondary CityMore Information57601MobridgeFoster57601MobridgeGopher57601MobridgePromiseAdvertisements