A sign along Taylorsville Road, advertising the city of Jeffersontown across the underside of a railroad bridge. Jeffersontown is a home rule-class city in Jefferson County, Kentucky, United States. The population was 26,595 at the 2010 U.S. census. A major suburb of Louisville, Jeffersontown retained its status as independent city when the Louisville Metro government formed in 2003. Louisville is Kentucky’s largest city, with a metro area population of 1,395,855 in 2020.