Known historically as "the Gateway to the Dakotas" Fort Abercrombie was the first permanent United States military fort established in what was to become North Dakota. It was also the only post in the area to be besieged by Dakota (Sioux) warriors for more than six weeks during the Dakota conflict of 1862. During the Dakota Conflict, Minnesota Volunteer soldiers manned the fort when area settlers sought shelter there. The "regular" U.S. Army soldiers had been withdrawn during the Civil War and had been replaced by the Minnesota Voluteer Infantry. The fort was not protected by blockhouses or a palisade during the siege, but these defensive structures were constructed soon afterward.