Sheridan Township is located in Logan County, Illinois. As of the 2010 census, its population was 477 and it contained 220 housing units.
According to the 2010 census, the township has a total area of , all land.
As of the 2020 census, there was a population of 466, with 191 households, and 131 families residing within the township. The racial makeup was 98.65% white, 0.22% African American, 0.22% Native American, 0.45% Asian, and 0.45% all other races.