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.