Bon Ayr is an unincorporated community in Barren County, Kentucky, United States. It was also known as Bonayer.
Bon Ayr is located in west-central Barren County at the crossroads intersection of U.S. Route 68 (which runs concurrently with Kentucky Route 80) and Kentucky Route 255. It is located about west-northwest of Glasgow.
Bon Ayr had a post office from 1890 to 1904.