| Official Name: | Annawan Township |
| Settlement Type: | Township |
| Image Map1: | Map of Illinois highlighting Henry County.svg |
| Mapsize1: | 150px |
| Map Caption1: | Henry County's location in Illinois |
| Subdivision Type: | Country |
| Subdivision Type1: | State |
| Subdivision Type2: | County |
| Subdivision Name2: | Henry |
| Established Title: | Established |
| Established Date: | November 4, 1856 |
| Unit Pref: | Imperial |
| Area Total Sq Mi: | 36.5 |
| Area Land Sq Mi: | 36.3 |
| Area Water Sq Mi: | 0.2 |
| Area Water Percent: | 0.55 |
| Population As Of: | 2010 |
| Population Density Sq Mi: | 30.6 |
| Elevation M: | 194 |
| Elevation Ft: | 636 |
| Coordinates: | 41.3722°N -89.9219°W |
| Timezone: | CST |
| Utc Offset: | -6 |
| Timezone Dst: | CDT |
| Utc Offset Dst: | -5 |
| Postal Code Type: | ZIP codes |
| Postal Code: | 61234, 61235, 61344, 61443 |
| Blank Name: | FIPS code |
| Blank Info: | 17-073-01582 |
| Pop Est As Of: | 2016 |
| Pop Est Footnotes: | [1] |
| Population Est: | 1084 |
Annawan Township is one of twenty-four townships in Henry County, Illinois, USA. As of the 2010 census, its population was 1,112 and it contained 515 housing units.[2]
According to the 2010 census, the township has a total area of, of which (or 99.45%) is land and (or 0.55%) is water.[2]