Carroll County is a county located in the northern part of the U.S. state of Kentucky. Its county seat is Carrollton. The county was formed in 1838 and named for Charles Carroll of Carrollton, the last living signer of the Declaration of Independence. It is located at the confluence of the Kentucky and Ohio Rivers.

Jefferson County is a county located in the U.S. state of Indiana. As of 2020, the population was 33,147. The county seat is Madison.