Frankfort is a city in Clinton County, Indiana, United States. It had a population of 16,715 as of the 2020 census. The city is the county seat of Clinton County. Brothers John, William and Nicholas Pence, previously of Warren County, Ohio, settled on the land on which Frankfort now stands in 1829, having entered it from the government in 1827 and 1828. In 1830, the brothers donated 60 acres of the land to the county commissioners, a donation which led to the establishment of the county seat at that site rather than in Jefferson, a community which had also been vying for the honor. The new town was named Frankfort at the brothers' request and honors their German great-grandparents' home of Frankfurt am Main.