After the
American Revolutionary War established US sovereignty over the territory of the upper midwest, the new federal government defined the
Northwest Territory in 1787 which included the area of present-day Indiana. In 1800, Congress separated Ohio from the Northwest Territory, designating the rest of the land as the Indiana Territory. President Thomas Jefferson chose William Henry Harrison as the governor of the territory, and Vincennes was established as the future capital. After the Michigan Territory was separated and the Illinois Territory was formed, Indiana was reduced to its current size and geography. By December 1816 the Indiana Territory was admitted to the Union as a state, although much of its territory was still in dispute as to possession by
Native Americans. The land containing Hendricks County was brought into the possession of the United States by the
Treaty of St. Mary's in 1818 (known as New Purchase). The eighth General Assembly of the new state of Indiana met at its then-capital town,
Corydon, in December 1823, and created three counties before the close of the session, among them being Hendricks, the state's fifty-first county. The bill creating Hendricks County was introduced in the Senate on December 9 and was signed on December 20 Until its governing structure was organized, the territory was assigned to neighboring counties for legislative and enforcement matters. Prior to the New Purchase treaty, the territory of Hendricks County had been occupied by the Dakota tribe, although there were no significant native villages within its future borders. The treaty authorized the territory to be surveyed by the federal government, with land being available for settlement thereafter. This survey work began in the Hendricks County area in 1819, and settlers began moving in as soon thereafter (the first in future Hendricks County in Spring 1820) as land filing was authorized, such that by 1823 there were sufficient inhabitants to justify forming a county. Designated commissioners met in July 1824, and on July 12 selected Danville as its county seat. The town plat was filed for record in October 1824; a court house was erected and in operation there by 1826. ==Geography==