Mount Zion Township is located in Macon County, Illinois. As of the 2010 census, its population was 7,131 and it contained 2,878 housing units. In 2009, Milam Township to the south was merged into Mount Zion Township.
According to the 2010 census, the township has a total area of , of which (or 99.97%) is land and (or 0.02%) is water.