Middletown is an eastern Jefferson county town and suburb of Louisville. The town was laid out in 1797 and was probably named for its location between Louisville and Shelbyville. For some years it was larger than Louisville. Middletown was incorporated in 1866, dissolved in 1962, and incorporated again in 1979. The Middletown post office opened in 1804 and closed in 1968. The population in 2010 was 7,218.