The City of Dayton, Kentucky, is a home rule-class city along a bend of the Ohio River in Campbell County, Kentucky, United States. The population was 5,666 at the 2020 census. It is less than 3 miles (5 km) from downtown Cincinnati, Ohio.

Campbell County is a county located in the northern part of the U.S. state of Kentucky. As of the 2020 census, the population was 93,076. Its county seats are Alexandria and Newport. The county was formed on December 17, 1794, from sections of Scott, Harrison, and Mason Counties and was named for Colonel John Campbell (1735–1799), a Revolutionary War soldier and Kentucky legislator. Campbell County, with Boone and Kenton Counties, is part of the Northern Kentucky metro community, and the Cincinnati-Middletown, OH-KY-IN Metropolitan Statistical Area.