The Northwest Territory, also known as the Old Northwest and formally known as the Territory Northwest of the River Ohio, was formed from unorganized western territory of the United States after the American Revolution. Established in 1787 by the Congress of the Confederation through the Northwest Ordinance, it was the nation's first post-colonial organized incorporated territory.
At the time of its creation, the territory included all the land west of Pennsylvania, northwest of the Ohio River and east of the Mississippi River below the Great Lakes, and what later became known as the Boundary Waters. The region was ceded to the United States in the Treaty of Paris of 1783. Throughout the Revolutionary War, the region was part of the British Province of Quebec and the western theater of the war. It spanned all or large parts of six eventual U.S. states (Ohio, Indiana, Illinois, Michigan, Wisconsin, and the northeastern part of Minnesota). Reduced to present-day Ohio, eastern Michigan and a sliver of southeastern Indiana with the formation of Indiana Territory July 4, 1800, it ceased to exist March 1, 1803, when the southeastern portion of the territory was admitted to the Union as the state of Ohio, and the remainder attached to Indiana Territory.
Initially, the territory was governed by martial law under a governor and three judges. As population increased, a legislature was formed as were a succession of counties, eventually totaling thirteen. At the time of its creation, the land within the territory was largely undisturbed by urban development. It was also home to several Native American cultures, including the Delaware, Miami, Potawatomi, Shawnee, and others; there were a handful of French colonial settlements remaining, plus Clarksville at the Falls of the Ohio. By the time of the territory's dissolution, there were dozens of towns and settlements, a few with thousands of settlers, chiefly along the Ohio and Miami Rivers and the south shore of Lake Erie in Ohio. Conflicts between settlers and Native American inhabitants of the Territory resulted in the Northwest Indian War culminating in General "Mad" Anthony Wayne's victory at Battle of Fallen Timbers in 1794. The subsequent Treaty of Greenville in 1795 opened the way for settlement particularly in southern and western Ohio.
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