August 27 is the anniversary of the day that marked the end of The Black Hawk War in 1832. This war marked the end of native resistance to the invaders in the old Northwest Territory (basically the land east of the Mississipi River).
The seeds of the war were sown years before in 1804 in the Treaty of St. Louis. I briefly mentioned it earlier. The US had extorted signing the land away from 5 native men who had no authority to sell the land. The local tribes never recognised the treaty as legitimate.
In 1832, things had gotten bad. The US was aggressively settling Sauk and Fox land, and the tribes recognised that their time was running out. Chief Black Hawk was determined to try to save some of their last remaining sacred land by resettling it before the land was sold to white settlers, which was their right under the illegitimate Treaty of St. Louis. The genocidal Illinois Governor John Reynolds had this to say:
If I am again compelled to call on the Militia of this State, I will place in the field such a force as will exterminate all Indians, who will not let us alone."
Chief Black Hawk crossed the river with his band of about 1100 men, women, and children. The US treated this as an invasion, and attacked. The war lasted less than 5 months. But in that time, John Reynolds did indeed do his best to make good on his promise of extermination. Over half of the band were slaughtered with minimal losses to their jackboots.
Chief Blackhawk surrendered on this day. He was paraded around the major US cities on the east coast like a trophy, then imprisoned for a year as punishment for trying to live on his traditional land. The villain Andrew Jackson used the war to push for more forced relocation of tribes located in the Old Northwest. The last to leave were the Dakotas, as discussed earlier. They had allied with the genocidal regime, which bought them time until it was decided that they had outlived their usefulness.