Irwin, Ohio
Irwin is an unincorporated community in southwestern Union Township, Union County, Ohio, United States. It is located at, at the intersection of Ohio State Route 4 and 161. Although it is unincorporated, Irwin has a post office which serves the surrounding area, including the community of Rosedale.History
A post office has been in operation at Irwin since 15 May 1858. The community was named for one Mr. Irwin, a pioneer settler.
Located near Irwin is Elmwood Place, a historic farm that is listed on the National Register of Historic Places.
