Arendahl Township is a township in Fillmore County, Minnesota, United States. The population was 333 at the 2000 census. Arendahl Township was organized in 1860, and named after Arendal, in Norway. According to the United States Census Bureau, the township has a total area of 35.8 square miles, of which 35.7 square miles is land and 0.1 square mileā¦Arendahl Township is a township in Fillmore County, Minnesota, United States. The population was 333 at the 2000 census. Arendahl Township was organized in 1860, and named after Arendal, in Norway. According to the United States Census Bureau, the township has a total area of 35.8 square miles, of which 35.7 square miles is land and 0.1 square miles is water.