Louisville, which merged with Jefferson County in 2003, is the largest city in Kentucky. It is situated at the Falls of the Ohio, at the Kentucky-Indiana border.

In 1778, Lt. Col. George Rogers Clark and his troops established Fort Nelson within the current boundaries of Louisville. The following year, the town was named for France's King Louis XVI, who supported the colonists in the Revolutionary War. Its location at the Ohio River's falls gave the city both military and economic importance. By the early 19th century, it had become a major river port. The completion of the Portland Canal around the falls in 1830 further stimulated its economic growth and cultural development.

Between 1956 and 1984, Jefferson County voters rejected three proposals to create a consolidated local government for the entire county. Finally, in 2000, they approved a merger between Jefferson County and the City of Louisville, until then the county seat. The new Louisville-Jefferson County Metro Government was formed on January 6, 2003.

The city is well known for horse racing (the Kentucky Derby has been held there since 1875), and is a leading producer of gin, whiskey, tobacco, and Louisville Slugger baseball bats. Other major exports include chemicals, rubber, paint, and electrical appliances. It is home to the American Printing House for the Blind, the world's largest publisher of books in Braille, and the Kentucky School for the Blind. The University of Louisville was the first city-owned university in the U.S., founded in 1798, and the Louisville Free Public Library was one of the first public systems in the country.