Harrison Township is one of six townships in Union County, Indiana, United States.

As of the 2020 census, its population was 429 and it contained 176 housing units.

[2] According to the 2010 census, the township has a total area of 30.13 square miles (78.0 km2), of which 30.11 square miles (78.0 km2) (or 99.93%) is land and 0.02 square miles (0.052 km2) (or 0.07%) is water.

[4] (This list is based on USGS data and may include former settlements.)

The township contains these two cemeteries: Nutter and Railsback.