Mercer County on the map of Illinois 2024. Cities, roads, borders and directions in Mercer County of Illinois.

Mercer County is situated on the western border of Illinois. This well known county was named after Hugh Mercer (1726-1777), British officer in the Seven Years' War and general in the Continental Army during the American Revolutionary War. The area of Mercer County is about 561 square miles. This county, set up in 1825, is populated today by 16 thousand residents. Aledo is the county seat of Mercer County. This map shows the borders of Mercer County as well as neighboring counties, including major highways and natural objecsts as of 2024. Zoom in or out of the map using the plus/minus panel. Move the center of this map by dragging it. Also check out the satellite map of Mercer County.