Greenville is a home rule-class city in Muhlenberg County, Kentucky, in the United States. It is the seat of its county. The population was 4,49…Greenville is a home rule-class city in Muhlenberg County, Kentucky, in the United States. It is the seat of its county. The population was 4,492 as of the 2020 census. The town was settled in 1799 on an estate donated by local landowner William Campbell in order to establish a seat of government for a new county. Greenville was not established by the state assembly until 1812, however. It was incorporated as a city in 1848.