St. Matthews is a city in Jefferson County, Kentucky, United States. It forms part of the Louisville Metro government but is separately incorp…St. Matthews is a city in Jefferson County, Kentucky, United States. It forms part of the Louisville Metro government but is separately incorporated as a home rule-class city. The population was 17,472 at the 2010 census, up from 15,852 at the 2000 census. It is the 23rd-largest city in the state. St. Matthews is one of the state's major shopping areas, home to the fifth-largest mall in Kentucky along with many smaller shopping centers along Shelbyville Road.