Boardman Township is a township in Clayton County, Iowa, United States. As of the 2000 census, its population was 1,832. Boardman Township is named for Elisha Boardman, who settled there in 1836. Boardman Township covers an area of 36.45 square miles and contains one incorporated settlement, Elkader. According to the USGS, it contains …Boardman Township is a township in Clayton County, Iowa, United States. As of the 2000 census, its population was 1,832. Boardman Township is named for Elisha Boardman, who settled there in 1836. Boardman Township covers an area of 36.45 square miles and contains one incorporated settlement, Elkader. According to the USGS, it contains three cemeteries: Eastside, Erhardt and Saint Josephs.