Illinois County Boundaries Maps from 1790-1859.

Illinois Boundary Changes:

1673 - Illinois Became a County of Virginia [New France] French: Pays des Illinois

1778 - Illinois Country - Ceded by Virginia

1784 - Northwest Territory

1800 - Indiana Territory

1809 - Illinois Territory

1818 - Illinois Becomes the 21st state, with Kaskaskia as the Capital.

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29 Individual Illinois Boundaries Maps 1790-1859