Frankfort is the capital city of the U.S. state of Kentucky. It is a home rule-class city and the seat of Franklin County. The population was 28,60…Frankfort is the capital city of the U.S. state of Kentucky. It is a home rule-class city and the seat of Franklin County. The population was 28,602 at the 2020 United States census, making it the 13th most populous city in Kentucky, and the 4th least populous U.S. state capital. Located along the Kentucky River, Frankfort is the principal city of the Frankfort, Kentucky micropolitan area, which includes all of Franklin and Anderson counties.