Before the Louisiana Purchase in 1803, the great American frontier was the Northwest Territory. Today it includes Ohio, Michigan, Illinois, Indiana, Wisconsin, and part of Minnesota. The Northwest Ordinance of 1787 said that citizens could buy land there, and any man who owned at least 50 acres of land could vote. The Ordinance ignored the rights of Native Americans who already lived there. But it also said the region would be free of slavery. By 1860, tens of thousands of free African Americans had settled in the Northwest Territory. Many came to farm.