Pierson Township is one of twelve townships in Vigo County, Indiana, United States. At the 2010 census, the population was 1,210 and it contained 589 housing units.
Frank Senour Round Barn was listed on the National Register of Historic Places in 1993.
According to the 2010 census, the township has a total area of , of which (or 98.19%) is land and (or 1.81%) is water.
The township contains these six cemeteries: Armstrong, Brown, Donham, Ruggles, Stephens and Taylor.