Holstein is a city in Ida County, Iowa, United States. The population was 1,501 in the 2020 census, a 2% increase from 1,470 in 2000. Holsteiā¦Holstein is a city in Ida County, Iowa, United States. The population was 1,501 in the 2020 census, a 2% increase from 1,470 in 2000. Holstein was founded in 1882. A large share of the early settlers being natives of Holstein, in Germany, caused the name to be selected. Holstein was incorporated as a city on April 25, 1883. The city celebrated its Quasquicentennial in June 2007 with a week-long series of events.