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). The Indiana Territory was the first new territory created from lands of the Northwest Territory, which had been organized under the terms of the Northwest Ordinance of 1787. The territorial capital was the settlement around the old French fort of Vincennes on the Wabash River, until transferred to Corydon near the Ohio River in 1813.

Indiana is a state in the Midwestern region of the United States. It borders Lake Michigan to the northwest, Michigan to the north and northeast, Ohio to the east, the Ohio River and Kentucky to the south and southeast, and the Wabash River and Illinois to the west. Nicknamed "the Hoosier State", Indiana is the 38th-largest by area and the 17th-most populous of the 50 states. Its capital and largest city is Indianapolis. Indiana was admitted to the United States as the 19th state on December 11, 1816.