From 1816-1862, the site was known as Fort Armstrong. Before that, successive cultures of Native Americans had occupied it for thousands of years because of its strategic position along the Mississippi River. The United States took control of the island in 1804 through the Harrison Peace Treaty with the Chief of the Fox and Sac Tribes. From 1804 to 1812, the US Army did not occupy the island. It was the scene of a small conflict at the outbreak of the War of 1812 with Great Britain. Following that war, in 1814, it was the site of a U.S. Army expedition from St Louis to use the island as a guard post to control traffic on the Mississippi and maintain watch over the local Native Americans. A total of 41 Confederate prisoners successfully escaped during the prison's operation, and many more would try but fail. They were deterred by the power of the Mississippi River. A total of 1,964 Confederate prisoners and 125 Union guards are buried in the adjacent military cemetery. The Union guard burials included 49 African-American members of the
108th Colored Infantry, who had served as guards. Most of the men died from disease, since sanitation was primitive, as in all army encampments. In addition, they were exposed to high heat and humidity during the summers and freezing temperatures during winters. In 1864, deadly
smallpox epidemics rapidly spread through the prison. The prison camp operated from December 1863 until July 1865, when the last prisoners were freed. After the war, the prison facility was completely destroyed. During its two years in operation, the prison camp housed a total of more than 12,400 Confederates. Other historical sites in the area include the Confederate Cemetery, the
Rock Island National Cemetery, 19th-century stone workshops, officers' quarters along the river, Col. Davenport's House, and the site of the
first railroad bridge built across the Mississippi. Following the war, the federal government retained ownership of Arsenal Island. It developed the property for use as an arsenal and ordnance manufacturing center, which led to the island being renamed. == Women's history ==