| Official Name: | Rio Township |
| Settlement Type: | Township |
| Image Map1: | Map of Illinois highlighting Knox County.svg |
| Mapsize1: | 150px |
| Map Caption1: | Knox County's location in Illinois |
| Subdivision Type: | Country |
| Subdivision Type1: | State |
| Subdivision Type2: | County |
| Subdivision Name2: | Knox |
| Established Title: | Established |
| Established Date: | November 2, 1852 |
| Unit Pref: | Imperial |
| Area Total Sq Mi: | 36.16 |
| Area Land Sq Mi: | 36.16 |
| Area Water Sq Mi: | 0 |
| Area Water Percent: | 0 |
| Population As Of: | 2010 |
| Population Density Sq Mi: | 14.3 |
| Elevation M: | 241 |
| Elevation Ft: | 791 |
| Coordinates: | 41.1053°N -90.3869°W |
| Timezone: | CST |
| Utc Offset: | -6 |
| Timezone Dst: | CDT |
| Utc Offset Dst: | -5 |
| Postal Code Type: | ZIP codes |
| Postal Code: | 61401, 61467, 61472, 61488 |
| Blank Name: | FIPS code |
| Blank Info: | 17-095-64161 |
| Pop Est As Of: | 2016 |
| Pop Est Footnotes: | [1] |
| Population Est: | 502 |
Rio Township is one of twenty-one townships in Knox County, Illinois, USA. As of the 2010 census, its population was 518 and it contained 235 housing units.[2]
According to the 2010 census, the township has a total area of, all land.[2]
The township contains these four cemeteries: Bruner, Deatherage, Rio Baptist and Rio.