Chemung Township is the northwesternmost township of McHenry County, Illinois, United States.
It includes the bulk and northern part of the city of Harvard, as well as unincorporated communities: Big Foot Prairie (partly in Wisconsin), Lawrence, and Chemung.
As of the 2020 census, its population was 9,035 and it contained 3,294 housing units.
According to the 2010 census, the township has a total area of , all land.