| Official Name: | St. Mary, 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: | Hancock |
| Timezone: | Central (CST) |
| Utc Offset: | -6 |
| Timezone Dst: | CDT |
| Utc Offset Dst: | -5 |
| Elevation Ft: | 571 |
| Coordinates: | 40.3461°N -90.9339°W |
| Area Code: | 217 |
| Blank Name: | GNIS feature ID |
| Blank Info: | 417530 |
St. Mary is an unincorporated community in St. Mary's Township, Hancock County, Illinois, United States. The community is located along County Route 6 3.9miles north of Plymouth.[1]