Cass Township is one of eleven townships in Clay County, Indiana. As of the 2020 census, its population was 346 (slightly down from 347 at 2010) and it contained 148 housing units.
Cass Township was organized in the 1840s. It was named for Lewis Cass.
The Indiana State Highway Bridge 42-11-3101 and Poland Presbyterian Church and Cemetery are listed on the National Register of Historic Places.
According to the 2010 census, the township has a total area of , all land.
(This list is based on USGS data and may include former settlements.)
The township contains 13 cemeteries: Cagle, Neir, Wilkinson-Nees, Poland Chapel, [Unnamed]. Anderson, Cromwell, Rizley, Old Mace, Dyer-Schopple, Syster, Union, & Latham-Lucas.