Dayton, KY. Sponsored Topics. Dayton is a city in Campbell County, Kentucky, United States, along a bend of the Ohio River. The population was 5,966 at the 2000 census. It is less than 2 miles (3.2 km) from downtown Cincinnati, Ohio. Dayton is located at 39°6′42″N 84°28′13″W / 39.11167°N 84.47028°W / 39.11167; -84.47028 (39.111781, -84.470401).