Mercer County is a county in Illinois. According to the 2020 census, it had a population of 15,699. Its county seat is Aledo.
Mercer County Courthouse
Aledo is a city in Mercer County, Illinois, United States. The population was 3,633 at the 2020 census. It is the county seat of Mercer County.
Mercer County Courthouse
Aerial view of Aledo, 2012