| Unit Pref: | Imperial |
| Settlement Type: | Township |
| Official Name: | Allin Township |
| Image Map1: | Map of Illinois highlighting McLean County.svg |
| Mapsize1: | 150px |
| Map Caption1: | McLean County's location in Illinois |
| Coordinates: | 40.4389°N -89.2086°W |
| Subdivision Type: | Country |
| Subdivision Name: | United States |
| Subdivision Type1: | State |
| Subdivision Name1: | Illinois |
| Subdivision Type2: | County |
| Subdivision Name2: | McLean |
| Leader Title: | Supervisor |
| Established Title: | Established |
| Established Date: | March 4, 1867 |
| Area Total Sq Mi: | 36.25 |
| Area Land Sq Mi: | 36.25 |
| Area Water Sq Mi: | 0 |
| Area Water Percent: | 0 |
| Population As Of: | 2010 |
| Population Density Sq Mi: | 25.4 |
| Utc Offset: | -6 |
| Timezone Dst: | CDT |
| Utc Offset Dst: | -5 |
| Pop Est As Of: | 2016 |
| Pop Est Footnotes: | [1] |
| Population Est: | 899 |
| Blank Name: | FIPS code |
| Blank Info: | 17-113-00893 |
Allin Township is located in McLean County, Illinois. As of the 2010 census, its population was 919 and it contained 389 housing units.[2] Allin Township was originally named Mosquito Grove Township, but changed its name on March 4, 1867. The township bears the name of James Allin, a promoter of Bloomington, Illinois.[3]
According to the 2010 census, the township has a total area of, all land.[2]