Aetna Township is located in Logan County, Illinois. As of the 2010 census, its population was 535 and it contained 228 housing units. Chestnut, Illinois and Bakerville, Illinois are the only communities in the township.
Aetna Township most likely derives its name from Mount Etna.
According to the 2010 census, the township has a total area of , all land.
According to the 2020 United States census, Aetna Township has a population of 476 in 212 houses. The employment rate was 50.7%.