The U.S. state of Indiana has 92 counties. Each county serves as the local level of government within its borders. Although Indiana was organized into the United States since the Northwest Ordinance in 1787, its land was not always available for settlement. Eventually, land was purchased from Native Americans by treaties and Indian removals. The oldest counties are generally in the south near the Ohio River, whereas newer ones were in the north in territory acquired later. The oldest and newest counties in Indiana are Knox County, created in 1790, and Newton County, created in 1859.