Ohio's 4th senatorial district has been based in southwestern Ohio and now consists of almost all of Butler County. It encompasses Ohio House of Representatives districts 51, 52 and 53. It has a Cook PVI of R+13. Its current Ohio Senator is Republican Bill Coley. He resides in Middletown, a city located in Butler and Warren counties.
References
Ohio's 4th senatorial district Wikipedia(Text) CC BY-SA