The battle, which occurred during the War of 1812, followed the evacuation of the fort as ordered by the commander of the United States Army of the Northwest, William Hull.

Following the battle, the federal government became convinced that all Indians had to be removed from the territory and the vicinity of any settlements, as settlers continued to migrate to the area.

[3][4] The British Empire had ceded the Northwest Territory, comprising what is now Ohio, Indiana, Illinois, Michigan, Wisconsin, and parts of Minnesota, to the United States at the Treaty of Paris in 1783.

[11] As the United States and Britain moved towards war, antipathy between the settlers and Native Americans in the Fort Dearborn area increased.

News of the murder was carried to Fort Dearborn by a soldier of the garrison, named John Kelso, and a small boy, who had managed to escape from the farm.

[14] Following the murder, some nearby settlers moved into the fort, and the rest fortified themselves in a house that had belonged to Charles Jouett, a Native American agent.

Fifteen men from the civilian population were organized into a militia by Captain Heald and were armed with guns and ammunition from the fort.

[n 1] Hull also sent a copy of these orders to Fort Wayne to the southeast of Lake Michigan, with additional instructions to provide Heald with all the information, advice and assistance within their power.

[13] The Native Americans believed that Heald told them that he would distribute the firearms, ammunition, provisions, and whiskey among them and that if they would send a band of Potawatomis to escort them safely to Fort Wayne, he would pay them a large sum of money.

However, Heald ordered all the surplus arms, ammunition, and liquor destroyed "fearing that [the Native Americans] would make bad use of it if put in their possession.

"[21] On August 14, a Potawatomi chief called Black Partridge warned Heald that the young men of the tribe intended to attack and that he could no longer restrain them.

[26] The maneuver separated the cavalry from the wagons, which allowed the overwhelming Native American force to charge into the gap, divide, and surround both groups.

According to eyewitness accounts, he fought off many Native Americans before being killed, and a group of Indians immediately cut out his heart and ate it to absorb his courage.

[31] Helm wrote a detailed narrative of events, but his fear of being court-martialed for his criticism of Heald made him delay publication until 1814.

Juliette Augusta Magill Kinzie's Wau-Bun: The Early Day in the Northwest, which was first published in 1856, provides the traditional account of the conflict.

The battle has been claimed a massacre due to the large number of Americans killed including women and children, as opposed to the relatively-smaller Potawatomi losses incurred.

[40] Juliette Kinzie, shortly before her death in 1870, stated that the battle had started by a large cottonwood tree, which still stood on 18th Street between Prairie Avenue and the lake.

[40] The historian Harry A. Musham points out that the testimony relating to the tree is all second hand and came from people who had settled in Chicago more than 20 years after the battle.

[45] The battle is also memorialized with a sculpture by Henry Hering, called Defense, which is located on the south western tender's house of the Michigan Avenue Bridge, which partially covers the site of Fort Dearborn.