| Official Name: | Marcus, Illinois |
| Settlement Type: | Unincorporated community |
| Pushpin Map: | Illinois#USA |
| Subdivision Type: | Country |
| Subdivision Name: | United States |
| Subdivision Type1: | State |
| Subdivision Name1: | Illinois |
| Subdivision Type2: | County |
| Subdivision Name2: | Carroll |
| Timezone: | Central (CST) |
| Utc Offset: | -6 |
| Timezone Dst: | CDT |
| Utc Offset Dst: | -5 |
| Elevation Ft: | 607 |
| Coordinates: | 42.1583°N -90.1958°W |
| Area Code: | 815 & 779 |
| Blank Name: | GNIS feature ID |
| Blank Info: | 422938[1] |
Marcus is an unincorporated community in Carroll County, Illinois, United States. Marcus is located between Illinois Route 84 and the Mississippi River, north of Savanna.