The Indiana Territory was a region established by the United States in 1800, encompassing parts of present-day Indiana, Illinois, Wisconsin, and Michigan. It was created to facilitate the settlement and governance of the area, which was previously part of the larger Northwest Territory. The territory played a crucial role in the westward expansion of the United States. The first governor of the Indiana Territory was William Henry Harrison, who served from 1800 to 1812. During this time, the territory experienced significant growth, with settlers moving in and establishing communities. The territory was eventually admitted to the Union as the state of Indiana in 1816.