The Native American groups, including Black Hawk, laid siege to Fort Madison for a number of weeks. At some point while the siege continued Black Hawk left for a while. After a number of weeks of being under a fairly ferocious attack, the Americans abandoned the fort, burned it down while leaving, and escaped out a trench to the Mississippi River.
The attack on Fort Madison was the only part of the War of 1812 that was fought in Iowa.
Other people may have been better educated in history than I was (and part of my ignorance may be my own fault), but prior to reading up on the subject I was under the impression that the war was fought over trade issues, and over the British Navy stopping ships and the forced impressments of American sailors.
That it was. But it was more than that. It was also a reaction of the Native Americans to the land-grabbing treaties that were initiated by William Henry Harrison with the authority of the American government. For the first time in history the natives formed a confederacy to coordinate their efforts, led by the Shawnee Prophet Tenskwataw and his brother Tecumseh. The natives joined with Great Britain in an attempt to push the Americans back. Black Hawk and about 200 warriors joined in on the side of the British, and Black Hawk even received a commission for his participation.
Meanwhile, back in Saukenuk and the villages scattered along the Mississippi, the Americans were in control. Some natives sided with the Americans while most tried to remain neutral.
The war ended badly for the natives, with the defeat and death of Tecumseh, and the abandonment of the cause by the British. The war was not a great victory for the Americans, either—it was mostly a stalemate. However, the defeat of the British in New Orleans by Andrew Jackson gave the Americans something to celebrate.