Louisville is the most populous city in the Commonwealth of Kentucky, sixth-most populous city in the Southeast, and the 27th-most-populous city in the United States. By land area, it is the country's 24th-largest city, although by population density, it is the 265th most dense city. Louisville is the historical county seat and, since 2003, the nominal seat of Jefferson County, on the Indiana border.

The Louisville and Nashville Railroad, commonly called the L&N, was a Class I railroad that operated freight and passenger services in the southeast United States.