| Official Name: | Duncan Mills, Illinois |
| Settlement Type: | Unincorporated community |
| Pushpin Map: | Illinois#USA |
| Pushpin Label: | Duncan Mills |
| Pushpin Label Position: | top |
| Subdivision Type: | Country |
| Subdivision Name: | United States |
| Subdivision Type1: | State |
| Subdivision Name1: | Illinois |
| Subdivision Type2: | County |
| Subdivision Name2: | Fulton |
| Timezone: | Central (CST) |
| Utc Offset: | -6 |
| Timezone Dst: | CDT |
| Utc Offset Dst: | -5 |
| Elevation Ft: | 479 |
| Coordinates: | 40.34°N -90.1908°W |
| Area Code: | 309 |
| Blank Name: | GNIS feature ID |
| Blank Info: | 407486 |
Duncan Mills is an unincorporated community in Fulton County, Illinois, United States. Duncan Mills is located at the junction of US 24, US 136, and IL 100 south of Lewistown.
A post office called Duncans Mills was established in 1858, and remained in operation until 1905.[1] The community was named for George Duncan, the owner of a local mill.[2]