Illinois County, Virginia, was a political and geographic region, part of the British Province of Quebec, claimed during the American Revolutionary War on July 4, 1778, by George Rogers Clark of the Virginia Militia as a result of the Illinois Campaign.
Though part or all of the area was also claimed by Connecticut and Massachusetts, it was formally organized by the Commonwealth of Virginia later that year.
[2] John Todd was appointed by Governor Patrick Henry to head the county's government.
[3] The county was abolished in January 1782, and Virginia ceded the land to the new United States Confederation government in 1784.
Politically, its effective reach extended only to the old French settlements of Vincennes, Cahokia, and Kaskaskia.