| Official Name: | Castle Fin, 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: | Clark |
| Timezone: | Central (CST) |
| Utc Offset: | -6 |
| Timezone Dst: | CDT |
| Utc Offset Dst: | -5 |
| Elevation Ft: | 630 |
| Coordinates: | 39.47°N -87.7333°W |
| Area Code: | 217 |
| Blank Name: | GNIS feature ID |
| Blank Info: | 422534 |
Castle Fin is an unincorporated community in Clark County, Illinois, United States. Castle Fin is 7miles north-northwest of Marshall. The community was founded by Robert Wilson and platted in 1848. Wilson named Castle Fin after his hometown of Castle Finn in County Donegal, Ireland.[1]