Olin is a city in Jones County, Iowa, United States. The population was 651 at the time of the 2020 census. It is part of the Cedar Rapids Met…Olin is a city in Jones County, Iowa, United States. The population was 651 at the time of the 2020 census. It is part of the Cedar Rapids Metropolitan Statistical Area. Olin is named for D. A. Olin, general superintendent of the Chicago, Milwaukee, St. Paul and Pacific Railroad.