The United States 32nd Infantry Division was formed from Army National Guard units from Wisconsin and Michigan and fought primarily during World War I and World War II. With roots as the Iron Brigade in the American Civil War, the division's ancestral units came to be referred to as the Iron Jaw Division. During tough combat in France in World War I, it soon acquired from the French the nickname Les Terribles, referring to its fortitude in advancing over terrain others could not. It was the first allied division to pierce the German Hindenburg Line of defense, and the 32nd then adopted its shoulder patch; a line shot through with a red arrow, to signify its tenacity in piercing the enemy line. It then became known as the Red Arrow Division.

The Iron Brigade, also known as The Black Hats, Black Hat Brigade, Iron Brigade of the West, and originally King's Wisconsin Brigade was an infantry brigade in the Union Army of the Potomac during the American Civil War. Although it fought entirely in the Eastern Theater, it was composed of regiments from three Western states that are now within the region of the Midwest. Noted for its excellent discipline, ferocity in battle, and extraordinarily strong morale, the Iron Brigade suffered 1,131 men killed out of 7,257 total enlistments: the highest percentage of loss suffered by any brigade in the United States Army during the war.