When Fort Dearborn was built in 1803, it was a military outpost in a landscape still occupied and controlled by Native people. The fort sat across the Chicago River from the fur trading post and was built within only six square miles of land that had been ceded in the 1795 Treaty of Greenville. All other land surrounding those six miles was still owned by Native people until future treaty cessions in 1816.

In the decade after the fort was built, Neshnabé people living in the area began to increasingly see it as a threat to their land and lifeways. These groups contested the Treaty of Greenville and argued that no representatives from Chicago were present at the treaty signing, and they grew increasingly frustrated with white settlers who had begun to farm the land and disrupt the environment that Native people had long maintained. These tensions erupted in the Battle of Fort Dearborn.

After the battle, Fort Dearborn was raided for what supplies had not been destroyed and the building was burned to the ground. The Neshnabé people who lived and traded in the area continued to do so with some non-Native relatives. Beyond the mouth of the river, the labor of the Potawatomi, Odawa Sauk, Ho-Chunk, Myaamia, and Kickapoo people made the fur industry in the city immensely profitable. When the Americans returned to Chicago in 1816 and rebuilt Fort Dearborn, they once again entered an already thriving market.