Illinois County Formation Maps
Try our genealogy search engine
Maps showing the formation of Illinois counties, including comprehensive county formation information, history and the origin of county names.
Illinois County Formation Maps- 1790 Illinois County Formation Map - showing St. Clair and Knox - as Counties of the Northwest Territory
- 1795 Illinois County Formation Map - showing Randolph - as a county of the Northwest Territory
- 1801 Illinois County Formation Map - showing St. Clair and Randolph - as counties of the Territory of Indiana
- 1803 Illinois County Formation Map - showing St. Clair and Randolph - as counties of the Territory of Indiana: boundaries changed
- 1809 Illinois County Formation Map - showing St. Clair and Randolph - as counties of the Territory of Indiana: A Proclamation
- 1812 Illinois County Formation Map - showing Madison, Gallatin, and Johnson as counties of Illinois Territory
- 1813 Illinois County Formation Map - showing County boundaries re-adjusted
- 1814-1815 Illinois County Formation Map - showing Edwards and White as counties of the Illinois Territory
- 1816 Illinois County Formation Map - showing Jackson, Pope, Monroe and Crawford as counties of the Illinois Territory
- 1817 Illinois County Formation Map - showing Bond as a county of the Illinois Territory
- 1818 Illinois County Formation Map - showing Franklin, Union and Washington as counties of the Illinois Territory
- 1819 Illinois County Formation Map - showing Alexander, Clark, Jefferson and Wayne as counties of the State of Illinois
- 1821 Illinois County Formation Map - showing Lawrence, Greene, Sangamon, Pike, Hamilton, Montgomery and Fayette as counties of the State of Illinois
- 1823 Illinois County Formation Map - showing Edgar, Marion, Fulton and Morgan as counties of the State of Illinois
- 1824 Illinois County Formation Map - showing Clay, Clinton, and Wabash as counties of the State of Illinois
- 1825 Illinois County Formation Map - showing ten new counties of the State of Illinois
- 1826 Illinois County Formation Map - showing Vermilion and McDonough as counties of the State of Illinois
- 1827 Illinois County Formation Map - showing Shelby, Perry, Tazewell and Jo Daviess as counties of the State of Illinois
- 1831 Illinois County Formation Map - showing nine new counties of the State of Illinois
- 1835 Illinois County Formation Map - showing Champaign and Iroquois as counties of the State of Illinois
- 1836 Illinois County Formation Map - showing six new counties of the State of Illinois
- 1839 Illinois County Formation Map - showing twenty-one new counties of the State of Illinois
- 1905 Illinois County Formation Map - showing fifteen new counties of the State of Illinois
History of Illinois County Formation
Counties of Illinois -- Dates of Formation
Origin of Illinois County Names