| Unit Pref: | Imperial |
| Settlement Type: | Township |
| Official Name: | Manlius Township |
| Image Map1: | Map of Illinois highlighting LaSalle County.svg |
| Mapsize1: | 150px |
| Map Caption1: | LaSalle County's location in Illinois |
| Subdivision Type: | Country |
| Subdivision Name: | United States |
| Subdivision Type1: | State |
| Subdivision Name1: | Illinois |
| Subdivision Type2: | County |
| Subdivision Name2: | LaSalle |
| Leader Title: | Supervisor |
| Established Title: | Established |
| Established Date: | November 6, 1849 |
| Area Total Sq Mi: | 24.33 |
| Area Land Sq Mi: | 23.81 |
| Area Water Sq Mi: | 0.51 |
| Area Water Percent: | 2.10 |
| Population As Of: | 2010 |
| Population Density Sq Mi: | 263.5 |
| Utc Offset: | -6 |
| Timezone Dst: | CDT |
| Utc Offset Dst: | -5 |
| Pop Est As Of: | 2016 |
| Pop Est Footnotes: | [1] |
| Population Est: | 6050 |
| Blank Name: | FIPS code |
| Blank Info: | 17-099-46448 |
Manlius Township is located in east-central LaSalle County, Illinois. As of the 2010 census, its population was 6,275 and it contained 2,782 housing units.[2] It contains the town of Seneca and the eastern part of Marseilles.
According to the 2010 census, the township has a total area of, of which (or 97.86%) is land and (or 2.10%) is water.[2]
The population is 5,652 people, 81% urban and 19% rural. White non-Hispanics make up the largest population with 97%, 0% black, American Indian 0.1%, 0.3% Asian, and 0.7% two or more races. There are 2,317 houses in the township. It has a total area of 23.8 sq. miles.