Indiana Territory
The Indiana Territory, officially the Territory of Indiana, was created by an organic act that President John Adams signed into law on May 7, 1800, to form an organized incorporated territory of the United States that existed from July 4, 1800, to December 11, 1816, when the remaining southeastern portion of the territory was admitted to the Union as the state of Indiana. The territory originally contained approximately 259,824 square miles (672,940 km2) of land, but its size was decreased when it was subdivided to create the Michigan Territory (1805) and the Illinois Territory (1809).