| Unit Pref: | Imperial |
| Settlement Type: | Township |
| Official Name: | Oneco Township |
| Subdivision Type: | Country |
| Subdivision Name: | United States |
| Subdivision Type1: | State |
| Subdivision Name1: | Illinois |
| Subdivision Type2: | County |
| Subdivision Name2: | Stephenson |
| Leader Title: | Supervisor |
| Leader Name: | James R. Setterstrom |
| Area Total Sq Mi: | 27.44 |
| Area Land Sq Mi: | 27.44 |
| Area Water Sq Mi: | 0 |
| Area Water Percent: | 0 |
| Population As Of: | 2010 |
| Population Density Sq Mi: | 48.5 |
| Utc Offset: | -6 |
| Timezone Dst: | CDT |
| Utc Offset Dst: | -5 |
| Coordinates: | 42.4856°N -89.6631°W |
| Elevation Ft: | 823 |
| Pop Est As Of: | 2016 |
| Pop Est Footnotes: | [1] |
| Population Est: | 1270 |
| Blank Name: | FIPS code |
| Blank Info: | 17-177-56120 |
Oneco Township is located in Stephenson County, Illinois. As of the 2010 census, its population was 1,331 and it contained 587 housing units.[2] The village of Orangeville, and the unincorporated community of Oneco are located in this township.
Oneco is Township 29 North, Range 7 and 8 (part) East of the Fourth Principal Meridian.
According to the 2010 census, the township has a total area of, all land.[2]