Red Hills State Park is in southeastern Illinois in Lawrence County. The county borders the state of Indiana to the east. This part of Illinois was once part of the Vincennes Tract, a tract of land that was ceded to the United States of America in 1795 by Native Americans. The Natives lost a series of battles to General Anthony Wayne. The treaty was signed in Greenville. The Treaty of Greeneville was signed by a number of tribes known as the Western Confederacy. The tribes in the confederacy included the Wyandot, Lenape, Shawnee, Odawa, Ojibwe, Potawatomi, Miami, Wea, Kickapoo and Kaskaskia. The natives agreed to relinquish their claim to land that was north of the Ohio River and east of an established line. That line passes through what is now Red Hills State Park. The area grew following a series of wars and treaties and came to be known as the Northwest Territory and comprised what is now the states of Ohio, Indiana, Michigan, Illinois, Wisconsin and part of Minnesota.