South Macon Township is located in Macon County, Illinois. As of the 2010 census, its population was at 1,457 and it contained 639 housing units. The city of Macon, Illinois is located in the South Macon Township.
According to the 2010 census, the township has a total area of , all of it is land.
As of the 2020 census, the township had a population of 1,468, consisting of 551 families and a total of 606 housing units.