121st Street in Claremont Township, South Dakota

121st Street in Brown County is an unclassified road. It runs in an east-west direction starting from 404th Avenue and crosses 405th Avenue, 406th Avenue, 407th Avenue, 408th Avenue, 409th Avenue, 410th Avenue and 411th Avenue and ends at 412th Avenue. 121st Street also exists in Garland Township and Columbia Township.