The
Territory Northwest of the River Ohio, more commonly known as the
Northwest Territory, was an
organized incorporated territory of the United States spanning most or large parts of six eventual
U.S. States. It existed legally from July 13, 1787, until March 1, 1803, when the southeastern portion of the territory was admitted to the
Union as the
state of Ohio, and the remainder was reorganized. Previously, it had been disputed between Great Britain and the French Crown—with portions claimed by the colonies of Maryland, Virginia, and Pennsylvania, and also claimed by the French as part of the
New France Province of Quebec furnishing one cause of the
French and Indian War and the
Seven Years' Wars. Further after 1763
under British rule, the territory provided one of the more popular causes of the American Revolution, motivating less established Americans to support independence, when it was set aside in the
Royal Proclamation of 1763 for use by
Native Americans. The region was assigned to the United States in the
Treaty of Paris of 1783, but sporadic westward emigrant settlements had already resumed late in the war after the
Iroquois Confederation's power was broken, and boomed soon after the Revolution ended as the westward traffic soon spurred expansion of the gateway trading post into the town of Brownsville, PA ---> as an key west of the mountains outfitting centre, so also stimulating the establishment of the eastern parts of the eventual
National Road by private investors. The
Cumberland–Brownsville toll road linked the water routes of the
Potomac River with the
Monongahela River of the Ohio/Mississippi riverine systems in the days when water travel was the only good alternative to walking and riding; and most of the territory and its successors was settled by emigrants passing through the
Cumberland Narrows, or along the Mohawk Valley in New York State.