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; however, 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 state line.
Since 2003, Louisville and Jefferson County have shared the same borders following a city-county merger. The consolidated government is officially called the Louisville/Jefferson County Metro Government, commonly known as Louisville Metro. The term "Jefferson County" is still used in some contexts, especially for incorporated cities outside the "balance" area that defines Louisville proper. The total population of the consolidated area was 782,969 at the 2020 census, while the balance area (excluding other incorporated cities) had a population of 633,045 and is often cited in national statistics. The Louisville metropolitan area, which includes 12 surrounding counties in Kentucky and Southern Indiana, has 1.39 million residents and is the 43rd-largest metropolitan area in the U.S.