Penn Township is a township in McLeod County, Minnesota, United States. The population was 309 at the 2000 census.There were 119 households out of which 30.3% had children under the age of 18 living with them, 57.1% were married couples living together, 7.6% had a female householder with no husband present, and 26.1% were non-families. 21.8% of all households were made up of individuals and 10.1% had someone living alone who was 65 years of age or older. The average household size was 2.60 and the average family size was 2.98.