Dwight Township is located in Livingston County, Illinois. As of the 2010 census, its population was 4,494 and it contained 1,961 housing units.
Dwight Township was named for Henry A. Dwight, Jr., of New York, as was the village of Dwight, Illinois. He was a brother engineer of R. P. Morgan, who was the founder of the town.
According to the 2010 census, the township has a total area of , of which (or 99.89%) is land and (or 0.11%) is water.