During the 1804 Pike expedition to survey the Mississippi river multiple islands had been noted as being strategically important. One of the islands that stood out from the rest due to its sheer size and composition; was Rock Island. The island known as Rock Island stood towering over the Mississippi river with bluffs up to 30 feet high above river level making it a natural fortress. Additionally, it stood at the lower end one of the most difficult rapids to navigate on the river which extended from the western end of the island to present day Le Claire. Boats travelling in both directions, up and down the river, would have to take their time over the rapids, making Rock Island a natural point for a new fort to potentially control river navigation. Thus, it was an ideal location for the Army to construct a frontier fort that came with the added benefit of being able to monitor local native tribes and trade in the area.

Following the battles of the Rock Island Rapids during the war of 1812, BVT BG Thomas Smith arrived at Rock Island in May of 1816 and chose to establish the new fort on the west side of the island. The new fort was to be one of many that were situated on the Upper Mississippi from St. Louis to Prairie du Chien. The construction of the fort began on 10 May when a detachment of troops from the 8th Infantry arrived. COL William Lawrence assumed command of the construction at Rock Island. Upon the fort's completion at Rock Island, it was named Fort Armstrong in honor of John Armstrong who had served as Secretary of War under President James Madison.

Fort Armstrong was typical in design for forts in the region with square blockhouses with hewn timbers and dovetailed corners. Major Stephen H. Long described Fort Armstrong as having only “two entire faces” with the others having natural fortifications provided by “cliffs of limestone [up to] 30 feet high.” The buildings of the fort included the blockhouse buildings as well as barracks and a headquarters building surrounding a parade square and common area. Batteries were situated on the river facing sides to provide defense from the waters, while sentries were stationed on the land-facing walls to guard against possible land assaults and surprise attacks.

At its peak, Fort Armstrong was the logistical home to approximately ten percent of the regular Army. The fort served to act as a waypoint for settlers travelling west while also regulating peace in the local region. The peak of activity at the fort came in 1832, when the Sauk War Chief Black Hawk led a group of individuals from settlements west of the Mississippi to reoccupy the village of Saukenuk. The interpretation of the Americans was that this was a declaration of war. The resulting Black Hawk War consisted of chasing Black Hawk and his group through Illinois and Wisconsin territories. Black Hawk was eventually captured following the Battle of Bad Axe and taken into custody.

The mission of the fort was complete with the reduced threat from attack, and it was subsequently abandoned in 1836. Following this abandonment, numerous instances of squatters took up residency in some of the old ruins of the fort. The fort was reoccupied from 1840 to 1845 as an ordnance depot but, following the transfer of this mission to a depot in St. Louis, the fort was abandoned once again. A series of fires totally destroyed the ruins by 1856.

Finally in 1916, for the centennial of the fort's establishment and U.S. government presence at Rock Island COL Hillman authorized the construction of a replica blockhouse at the lower end of the island. Of all of the items associated with the original fort, however, only a few graves that had been relocated and a piece of timber in the Rock Island Arsenal Museum remain today.

Fort Armstrong was the first permanent presence of the U.S. government at Rock Island; a presence which continues to this day.


History Office, Army Sustainment Command. An Illustrated History of the Rock Island Arsenal and Arsenal Island. Rock Island Arsenal, Illinois. 2010. pp20-44.

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