The second group is made up of the tribes from eastern Illinois Country, which includes the Miami, Wea, Kickapoo, Mascouten, and Piankashaw.

Like the Great Lakes tribes, these people have a long history of close trading and other relations with the French.

Throughout the war, the British will be unable to project military power into the Illinois Country, which is on the remote western edge of the conflict.

The Illinois tribes will be the last to come to terms with the British.

The garrison at Vincennes along the Wabash River surrenders to Clark in August.

Several other villages and British forts will subsequently be captured, after most of the French-speaking and native inhabitants refuse to take up arms on behalf of the British.

Hamilton, to counter Clark's advance, recaptures the garrison at Vincennes, which the British call Fort Sackville, with a small force in December 1778.

Clark and his men had arrived at Vincennes on February 23, and launched a surprise attack on Fort Sackville.

Hamilton, who surrenders the garrison on February 25, is captured in the process.

The winter expedition, Clark's most significant military achievement, becomes the basis of his reputation as an early American military hero.

Slavery had been tolerated when the United States first took control of the Northwest Territory as a necessity to keep peace with the natives and the French.

When Indiana Territory was established in 1800, William Henry Harrison, a slaveholder, had been appointed governor and slavery has become largely accepted through a series of laws enacted by the appointed legislature.

Harrison had moved to Vincennes, the capital of the newly established Indiana Territory, on January 10, 1801.

While in Vincennes, Harrison builds a plantation style home he names Grouseland for its many birds.

It is one of the first brick structures in the territory.

The home (today restored and a popular modern tourist attraction) serves as the center of social and political life in the territory.

He also builds a second home near Corydon, the second capital, at Harrison Valley.

As governor, Harrison has wide ranging powers in the new territory, including the authority to appoint all territorial officials, and the territorial legislature, and to control the division of the territory into political districts.

A primary responsibility is to obtain title to native lands.

This will allow American settlement to expand and increase U.S. population to enable the region to gain statehood.

Harrison is eager to expand the territory for personal reasons as well, as his political fortunes are tied to Indiana's rise to statehood.

In 1803, President Thomas Jefferson had granted Harrison authority to negotiate and conclude treaties with the natives.

Harrison has supervised the development of thirteen treaties, through which the territory has purchased more than 60,000,000 acres (240,000 km2) of land from native leaders, including much of present-day southern Indiana.

The 1804 Treaty of St. Louis with Quashquame leads to the surrender by the Sauk and Meskwaki of much of western Illinois and parts of Missouri.

This treaty and loss of lands are greatly resented by many of the Sauk, especially Black Hawk, and will be the primary reason the Sauk side with Great Britain during the War of 1812.

Harrison thinks the Treaty of Grouseland in 1805 had appeased some of the issues for natives, but tensions remain high on the frontier.

The 1809 Treaty of Fort Wayne raised new tensions.

Harrison purchases from the Miami tribe, who claim ownership of the land, more than two and a half million acres (ten thousand square kilometers) of land inhabited by Shawnee, Kickapoo, Wea, and Piankeshaw peoples.

Harrison rushes the process by offering large subsidies to the tribes and their leaders so that he could have the treaty in place before President Jefferson leaves office and the administration changes.

The tribes living on the lands are furious and seek to have the treaty overturned but are unsuccessful.

Harrison ignores a protest made by Tecumseh.

Opposition against slavery had begun to organize in Indiana around 1805, and in 1809 abolitionists take control of the territorial legislature and overturn many of the pro-slavery laws.

Congress had organized the Northwest Territory in 1787 under the Northwest Ordinance, which had prohibited slavery by stating "that there shall be neither slavery nor involuntary servitude in the said territory".

It was later decided that anyone who purchased a slave outside of the territory could enter and reside there with their slaves.

The Ordinance had also allowed for preexisting French–native slave arrangements.

Many Virginian natives living in the Indian Territory have interpreted the Ordinance as allowing them to have slaves.

The Ordinance states that the Virginians "shall have their possessions and titles confirmed to them, and be protected in the enjoyment of their rights and liberties."

Many, therefore, decide to keep slaves.

Fear of French rebellion had kept the courts from acting against slavery, as did the violent actions of those who would kidnap escaped slaves.

A court ruling in the Michigan Territory in 1807 had stated that preexisting slavery could still exist under the Northwest Ordinance, validated Hoosier slaveholding in the opinions of the slaveholders.

Many of the territory's early settlers had come from the South.

Southern immigrants who were anti-slavery had settled in Ohio, where a strong anti-slavery movement is underway.

The immigrants in favor of slavery have generally moved to Indiana, where the government is friendly to slaveholders.

When they relocate to the Indiana Territory, they bring with them what few slaves they own.

An 1810 census records three hundred and ninety-three free blacks and two hundred and thirty-seven slaves in the Indiana Territory.

Knox County, where the territorial capital of Indiana, Vincennes, is located, is the center of Indiana slavery.

A young Army officer named Charles Larrabee, who is serving in Governor William Henry Harrison’s army, categorizes the Vincennes populace as “chiefly from Kentucky and Virginia…slavery is tolerated here.” (McCord, Shirley S. ed. (1970). Travel Accounts of Indiana 1679–1961. Indiana Historical Bureau.)