The largest of these was the Northwest Territory, which was progressively divided into several smaller territories by the United States Congress.
In 1800, the Indiana Territory was the first new territory established from a portion of the Northwest Territory.
At that time, Britain ceded the entire trans-Allegheny region, including what is now Indiana, to the new United States.
The United States government divided the trans-Allegheny region into several new territories.
After France ruled for 100 years (with little settlement in this area), it was defeated by Great Britain in the French and Indian War (Seven Years' War) and ceded its territory east of the Mississippi.