The Territory of Illinois was an organized incorporated territory of the United States that existed from 1 March 1809, until 3 December 1818, when the southern portion of the territory was admitted to the Union as the State of Illinois. The area was earlier known as "Illinois Country" while under French control, first as part of French Canada and then as part of Louisiana. The British gained authority over the region with the 1763 Treaty of Paris, marking the end of the French and Indian War. During the American Revolutionary War, Colonel George Rogers Clark took possession of the entire Illinois Country for Virginia, which established the "County of Illinois" to exercise nominal governance over the area. Virginia later ceded nearly all of its claims to land north of the Ohio River to the Federal government of the United States in order to satisfy objections of land-locked states. The area had been a part of the larger Northwest Territory (from 13 July 1787 until 4 July 1800), and then part of the Indiana Territory as Ohio prepared to become a state. On 3 February 1809, the 10th United States Congress passed legislation establishing the Illinois Territory, after Congress received petitions from residents in the far western areas complaining of the difficulties of participating in territorial affairs.
The Illinois Territory originally included lands that became the states of Illinois, Wisconsin, the eastern portion of Minnesota, and the western portion of the upper peninsula of Michigan. As Illinois was preparing to become a state, the remaining area of the territory was attached to the Michigan Territory.
The original boundaries of the Territory were defined as follows: “...all that part of the Indiana Territory which lies west of the Wabash river, and a direct line drawn from the said Wabash river and Post Vincennes, due north to the territorial line between the United States and Canada...”
These were the secretaries of Illinois Territory:
End of the Territory
- Historic regions of the United States
- History of Illinois
- Illinois Country
- Illinois Territory's At-large congressional district
- Illinois-Wabash Company
- Military Tract of 1812
- Territorial evolution of the United States
- War of 1812
- Heidler, David Steohen and Heidler, Jeanne T., eds. "Illinois Territory," Encyclopedia of the War of 1812, (2004), Naval Institute Press, Online at Google Book Search, Accessed 10 March 2009, http://books.google.com/books?id=_c09EJgek50C
- Edwards, Ninian Wirt. History of Illinois, from 1778 to 1833; and Life and Times of Ninian Edwards. p. 28. Retrieved 2008-02-24.
- Act dividing Indiana Territory, 1809
- An Act to enable the people of the Illinois Territory to form a constitution and state government, and for the admission of such state into the Union on an equal footing with the original states (April 18, 1818)
- Resolution declaring the admission of the state of Illinois into the Union (December 3, 1818)
- Solon J. Buck: Illinois in 1818
- Animated Map: Boundaries of the United States and the Several States