Louisville is the largest city in the U.S. state of Kentucky, and the county seat of Jefferson County. Since 2003, the city's borders have been coterminous with those of the county because of a city-county merger. The city's total consolidated population at the 2010 census was 741,096 (Louisville's balance total, 597,337, excludes semi-autonomous towns and is the population listed in most sources and national rankings). An important internal shipping port in the 19th century, Louisville today is best known as the location of the Kentucky Derby, the first of three annual thoroughbred horse races making up the Triple Crown.

Louisville is southeasterly situated along the border between Kentucky and Indiana, the Ohio River, in north-central Kentucky at the Falls of the Ohio. The Louisville metropolitan area is often referred to as Kentuckiana because it includes counties in Southern Indiana. A resident of Louisville is referred to as a Louisvillian. Although situated in a Southern state, Louisville is influenced by both Southern and Midwestern culture. It is sometimes referred to as either the northernmost Southern city or the southernmost Northern city in the United States.

The settlement that became the city of Louisville was founded in 1778 by George Rogers Clark and is named after King Louis XVI of France, making Louisville one of the oldest cities west of the Appalachian Mountains.