- Mercer County, Illinois, USA Location within Illinois Township Map Community Map Communities Roosevelt Military Academy Mercer County in the Civil War Aledo Time Golden Oaks Farm Wendy's Dog Grooming Suzy Bogguss Mercer County Courthouse, Aledo. Photo courtesy of Aledo Chamber of Commerce. Named for Hugh Mercer Hugh Mercer was a physician. A general during the American Revolution, Mercer was ...www.outfitters.com/illinois/mercer