Fort Thomas is a home rule-class city in Campbell County, Kentucky, United States, on the southern bank of the Ohio River and the site of an 1890 US Army post. The population was 17,483 at the 2020 census, making it the largest city in Campbell County. It is part of the Cincinnati – Northern Kentucky metropolitan area.

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.