Illinois County Boundaries 1790

1790 (N.W. Terr.) St.Clair, Knox	1795 (N.W. Terr.) Randolph	1801 (Indiana Terr.)	1803 (Indiana Terr.)	1809 (Illinois Terr.) Knox extinct	1812 (Illinois Terr.) Madison, Gallatin, Johnson
1813 (Illinois Terr.)	1815 (Illinois Terr.) Edwards (1814), White	1816 (Illinois Terr.) Monroe, Jackson, Pope, Crawford	1817 (Illinois Terr.) Bond	1818 (Illinois Terr.) Franklin, Union, Washington Statehood	1819 Alexander, Clark, Jefferson, Wayne
1821 Lawrence, Greene, Sangamon, Pike, Hamilton, Montgomery, Fayette	1823 Edgar, Marion, Fulton, Morgan	1824 Clay, Clinton, Wabash	1825 Calhoun, Adams, Hancock, Henry, Knox, Mercer, Peoria, Putnam, Schuyler, Warren	1826 Vermilion, McDonough	1827 Shelby, Perry, Tazewell, JoDaviess
1829 Macoupin, Macon	1831 Coles (1830), McLean (1830), Cook, LaSalle, Rock Island, Effingham, Jasper	1833 Champaign, Iroquois	1836 Will, Kane, McHenry, Ogle, Whiteside, Winnebago	1837 Livingston, Bureau, Cass, Boone, DeKalb, Stephenson	1839 Marshall, Brown, DuPage, Dane / Christian, Logan, Menard, Scott, Carroll, Lee, Jersey, Warren, Williamson, DeWitt, Lake, Hardin, Stark
1841 Henderson, Mason, Piatt, Grundy, Kendall, Richland, Woodford	1843 Massac, Moultrie, Cumberland, Pulaski	1847 Saline	1853 Kankakee	1859 (to present) Douglas, Ford	All Load all maps at once (may take a while to load)