Fort Armstrong was built in 1816 and was one of a system of forts on the Mississippi River. Fort Armstrong's role was fulfilled after it served as the military headquarters during the Black Hawk War. It was abandoned in 1836, but remained an ordnance depot until 1845. In 1916, a replica of one of the blockhouses from Fort Armstrong was erected where the fort once stood. HistoryConstruction of Fort Armstrong began in May 1816. The fort was named after John Armstrong, the Secretary of War under President James Monroe. The land that Fort Armstrong occupied was previously a resort for Sac and Fox Indians. The tribe's capital of Saukenuk was located about five miles south of Rock Island (now Arsenal Island).The location of Fort Armstrong, on the western tip of Arsenal Island, was selected based on recommendations and surveys by Zebulon Pike and Robert E. Lee. The Rock Island Rapids provided a natural navigational pause, which allowed the fort's location as well as points north to be more easily defended. The vast number of resources available on Rock Island and the surrounding area also provided a rich location on which to build. With the Rock River situated further south, Fort Armstrong's location was such that it allowed the American forces to dominate the Mississippi River.The primary function of Fort Armstrong was to provide security to American soldiers, settlers and commerce traversing the Mississippi River. However, relationships with the Sac and Fox Indians deteriorated. In 1832, Black Hawk, war chief of the Sac tribe, crossed the Mississippi River to reoccupy Saukenuk. The Americans took this as a hostile action, triggering the Black Hawk War.With the resolution of the Black Hawk War, Fort Armstrong was no longer needed, and so was abandoned. The ruins were used by squatters, until a fire destroyed what remained of the fort in 1854. The replica blockhouse was constructed in 1916 in celebration of Fort Armstrong's centennial.Fort Armstrong FactsFirst Built: 1816 Abandoned: 1832 Destroyed: 1854 Rebuilt: 1916 Namesake: John Armstrong, Secretary of War Layout: 3 Blockhouses; 6 Living Quarters; 1 Headquarters Staff: 200 soldiers Conflict: The Black Hawk War of 1832 Construction: White Oak Logs