| Official Name: | Irwin, Ohio |
| Settlement Type: | Unincorporated community |
| Mapsize: | 250px |
| Subdivision Type: | Country |
| Subdivision Name: | United States |
| Subdivision Type1: | State |
| Subdivision Name1: | Ohio |
| Subdivision Type2: | Counties |
| Subdivision Name2: | Union |
| Unit Pref: | Imperial |
| Timezone: | Eastern (EST) |
| Utc Offset: | -5 |
| Timezone Dst: | EDT |
| Utc Offset Dst: | -4 |
| Elevation Ft: | 1011 |
| Coordinates: | 40.1225°N -83.4894°W |
| Postal Code Type: | ZIP code |
| Postal Code: | 43029[1] |
| Area Code: | 614 |
| Blank Name: | GNIS feature ID |
| Blank Info: | 1064891 |
Irwin is an unincorporated community in southwestern Union Township, Union County, Ohio, United States. It is located at the intersection of Ohio State Route 4 and 161.[2] Irwin has a post office which serves the surrounding area, including the community of Rosedale.
A post office has been in operation at Irwin since 15 May 1858. The community was named for one Mr. Irwin, a pioneer settler.[3]
Located near Irwin is Elmwood Place, a historic farm that is listed on the National Register of Historic Places.