Serena Township is located in LaSalle County, Illinois. As of the 2010 census, its population was 1,138 and it contained 459 housing units. Serena Township changed its name from Warren Township in May, 1850.
According to the 2010 census, the township has a total area of 37.42 square miles (96.9 km2), of which 37.17 square miles (96.3 km2) (or 99.33%) is land and 0.25 square miles (0.65 km2) (or 0.67%) is water.
Serena Township is governed from the Village of Serena. The village has been incorporated since the early 1830s, and the Township Hall is located within town. The township has the Serena Fire Protection District, which serves nearby Northville, Mission, Miller, and Freedom Townships. Community Unit School District No. 2, which serves the area, is also headquartered in Serena, with the main High School for the district, as well as a Middle School and Elementary School located there as well. The township has US Highway 52 running through it as well.