Northwest Territory

A historical region of the north-central United States extending from the Ohio and Mississippi rivers to the Great Lakes. The area was ceded to the United States by the Treaty of Paris in 1783. It was officially designated a territory in 1787 and later split up into the territories and present-day states of Ohio, Indiana, Illinois, Michigan, Wisconsin, and part of Minnesota. Control over the territory was a major issue in the War of 1812.