Towanda Township is located in McLean County, Illinois. As of the 2010 census, its population was 1,296 and it contained 555 housing units. It contains the entirety of the town of Towanda and a portion of the town of Normal.
According to the 2010 census, the township has a total area of , all land.
As of the 2020 Census, Towanda Township's population was 2,006.