High Quality Content by WIKIPEDIA articles! Apple River Fort, today known as the Apple River Fort State Historic Site, was one of many frontier forts hastily completed by settlers in northern Illinois and southern Wisconsin following the onset of the 1832 Black Hawk War. Located in present-day Elizabeth, Illinois, United States, the fort at the Apple River settlement was built in less than a week. It was one of the few forts attacked during the war and the only one attacked by a band led by Black Hawk himself. At the Battle of Apple River Fort, a 45 minute firefight ensued, with Black Hawk`s forces eventually withdrawing. The fort suffered one militia man killed in action. After the war the fort stood until 1847, being occupied by squatters before being sold to a private property owner who dismantled the building.