Harrison Township is one of seventeen townships in Boone County, Iowa, USA. As of the 2000 census, its population was 368.
Harrison Township was organized in 1871. It is named for William Henry Harrison, ninth President of the United States.
Harrison Township covers an area of 35.97 square miles (93.2 km2) and contains no incorporated settlements. According to the USGS, it contains three cemeteries: Mackey, Saint Paul's Lutheran and Saints Peter and Paul.