The title of Iron Brigade has been given to a number of different US Army brigades over the last century and a half, but it has become almost entirely synonymous with the Civil War soldiers who fought in the brigade for the Army of the Potomac. Also known as the Iron Brigade of the West, Rufus King’s Brigade and the Black Hat Brigade, the Iron Brigade was comprised of the 2nd, 6th, and 7th Wisconsin Volunteer Infantry Regiments, the 19th Indiana, Battery B of the 4th US Light Artillery, and later, the 24th Michigan.

Wisconsin governor Alexander William Randall had hoped to organize an all-Wisconsin brigade to contribute to the Union's Civil War effort, but the US Army dispersed Wisconsin regiments to different areas as needs arose. Nevertheless, Wisconsin regiments comprised a majority of the brigade, and it would distinguish itself as the only all-Western brigade in the Army of the Potomac. It would come to be recognized for its unique uniforms, strong discipline, and iron disposition, earning the name during the Maryland Campaign both for its tenacity and for the costs paid by fighting so hard.

Naturally, historians have focused on the battles where the Iron Brigade earned its name and demonstrated its reputation. Renowned Civil War historian Alan T. Nolan wrote and published the most complete military history of the Iron Brigade in 1961, tracing the brigade's activity in the Civil War from the first mustering of Wisconsin regiments to the battle of Gettysburg. Nolan's The Iron Brigade: A Military History served as the authority on Iron Brigade history for decades and called Gettysburg the Iron Brigade's last stand, arguing that the battle was where the brigade lost its Western character. Since the publication of Nolan’s book in 1961, however, new sources - including letters and journals of men in the brigade - have been discovered, providing new depth to the history of the Iron Brigade. Thus, scholars in more recent years have contributed to the history of the Iron Brigade by focusing on the character and contributions of different regiments within the Iron Brigade, or by picking up where Nolan left off at the Battle of Gettysburg. Historians like Lance J. Herdegen argue that there is much more to be learned about the Iron Brigade by examining its struggle in the years after Gettysburg. In The Iron Brigade in Civil War and Memory: The Black Hats from Bull Run to Appomattox and Thereafter (2012), Herdegen provides a deeper account not only of the remnants of the Iron Brigade in the last two years of the Civil War, but also of its individual soldiers during and after the war. Exploring the experiences of members of the Iron Brigade before, during and after the Civil War contributes to a better understanding of their rise to fame and glory, and the cost of their sacrifice.