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.

Notably, the Miami tribal capital along with British trading posts was at Kekionga, at the site of present-day Fort Wayne, Indiana.

Integration of the Northwest Territory into a political unit, and settlement, depended on three factors: relinquishment by the British, extinguishment of states' claims west of the Appalachians, and usurpation or purchase of lands from the Native Americans.

In February 1779, George Rogers Clark, leading a force of Virginia militia, captured Kaskaskia and Vincennes from British commander Henry Hamilton.

As a concession to obtain ratification, these states ceded their claims on the territory to the federal government: New York in 1780, Virginia in 1784, and Massachusetts and Connecticut in 1785.

Some older French communities' property claims based on earlier systems of long, narrow lots also were retained.

The rest of the Northwest Territory was divided into roughly uniform square townships and sections, which facilitated land sales and development.

The young United States government, deeply in debt following the Revolutionary War and lacking authority to tax under the Articles of Confederation, planned to raise revenue from the methodical sale of land in the Northwest Territory.

[9] The Northwest Territory's first governor, Arthur St. Clair, sought to end Native American claims to Ohio land and thus clear the way for white settlement.

Mutual hostilities led to a campaign by General Josiah Harmar, whose 1,500 militiamen were defeated by the Native Americans in October 1790.

Rufus Putnam wrote to President Washington that "we shall be so reduced and discouraged as to give up the settlement [Marietta following the Big Bottom disaster].

One month later, near modern-day Fort Recovery, his force advanced to the location of Native American settlements near the headwaters of the Wabash River.

Although an investigation exonerated him, St. Clair resigned his army commission in March 1792 at the request of President Washington, but continued to serve as Governor of the Northwest Territory.

The military campaign of Gen. Wayne against the Western Confederacy, who were supported by a company of troops from Lower Canada, culminated with victory at the Battle of Fallen Timbers in 1794.

The following year, the Treaty of Greenville secured peace on the western frontier and opened most of southern and eastern Ohio for American settlement.

A gateway trading post developed as the town of Brownsville, Pennsylvania, which was a key outfitting center west of the mountains.

Other wagon roads, such as the Kittanning Path surmounting the gaps of the Allegheny in central Pennsylvania, or trails along the Mohawk River in New York, enabled a steady stream of settlers to reach the near west and the lands bordering the Mississippi.

The first land grant was to George Rogers Clark in 1781 at Falls of the Ohio on the Indiana side; he went on to found the settlement of Clarksville.

The Northwest Territory doubled the size of the United States, and establishing it as free of slavery proved to be of tremendous importance in the following decades.

In 1802, his opposition to plans for Ohio statehood led President Thomas Jefferson to remove him from office as territorial governor.

The first Ohio Constitution provided for a weak governor and a strong legislature, in part a reaction to St. Clair's method of governance.

On April 30, 1802, Congress passed an enabling act for Ohio that authorized the residents of the eastern portion of the Northwest Territory to form a state constitution and government, and be admitted to the Union.

In particular, it defined the bodies of government, established the legal basis of land ownership, provided for abolition and transfer of state territorial claims, made rules for admission of new states, established public education, recognized and codified 'natural rights', prohibited slavery, and defined the land rights and applicability of laws to the Native Americans.

The square surveys of the Northwest Territory became a hallmark of the Midwest, as sections, townships, counties (and states) were laid out scientifically, and land was sold quickly and efficiently (although not without some speculative aberrations).

[33] There were three secretaries: Winthrop Sargent (July 9, 1788 – May 31, 1798); William Henry Harrison (June 29, 1798 – December 31, 1799); and Charles Willing Byrd (January 1, 1800 – March 1, 1803).

Ebenezer Sproat was the first sheriff, Paul Fearing became the first attorney to practice in the territory, and Colonel William Stacy was foreman of the first grand jury.

Once the population of free men living within the territory rose to 5000, the federal government allowed residents to elect a legislature.

Both of these proposed acts were supported by a variety of influential members of congress including Thomas Jefferson in the hope that slavery would fade as the nation grew.

Article 3 stated, "Religion, morality, and knowledge being necessary to good government and the happiness of mankind, schools and the means of education shall forever be encouraged."

A sliver of Hamilton County along the southwestern border (the Greenville Treaty line) comprising a portion of the Whitewater River drainage basin and known as "The Gore" was also ceded to Indiana Territory.