Saint Marys Township is one of twelve townships in Adams County, Indiana.

[2] As of the 2020 census, its population was 1,269,[1] down from 1,308 at the 2010 census.

[3] According to the 2010 census, the township has a total area of 24.58 square miles (63.7 km2), of which 24.57 square miles (63.6 km2) (or 99.96%) is land and 0.01 square miles (0.026 km2) (or 0.04%) is water.

[4]