| Official Name: | Monticello Township |
| Settlement Type: | Township |
| Image Map1: | Map of Illinois highlighting Piatt County.svg |
| Mapsize1: | 150px |
| Map Caption1: | Piatt County's location in Illinois |
| Coordinates: | 40.0094°N -88.5381°W |
| Subdivision Type: | Country |
| Subdivision Name: | United States |
| Subdivision Type1: | State |
| Subdivision Name1: | Illinois |
| Subdivision Type2: | County |
| Subdivision Name2: | Piatt |
| Established Title: | Established |
| Established Date: | November 8, 1859 |
| Area Total Sq Mi: | 48.11 |
| Area Land Sq Mi: | 48.05 |
| Area Water Sq Mi: | 0.06 |
| Area Water Percent: | 0.12 |
| Elevation M: | 217 |
| Elevation Ft: | 712 |
| Population As Of: | 2010 |
| Population Density Sq Mi: | 122.9 |
| Timezone: | CST |
| Utc Offset: | -6 |
| Timezone Dst: | CDT |
| Utc Offset Dst: | -5 |
| Blank Name: | FIPS code |
| Blank Info: | 17-147-50257 |
| Pop Est As Of: | 2016 |
| Pop Est Footnotes: | [1] |
| Population Est: | 5940 |
| Unit Pref: | Imperial |
Monticello Township is a township in Piatt County, Illinois, USA. As of the 2010 census, its population was 5,906 and it contained 2,651 housing units.[2]
Monticello is Township 18 North, Range 6 East and part of Township 18 North, Range 5 East of the Third Principal Meridian.
According to the 2010 census, the township has a total area of, of which (or 99.88%) is land and (or 0.12%) is water.[2] The streams of Camp Creek and Goose Creek are tributaries of the Sangamon River which runs through this township.
The township contains several cemeteries: Haneline (Section 14, T. 18 N., R. 5 E.), Monticello, Monticello and Woolington.Barnes Cemetery is in Section 1, T. 18 N., R. 6 E.
Haneline School No. 69 (Section 23, T. 18 N., R. 5 E.), a brick building, is now a residence on Allerton Road.