Share This Article

Unmatched bravery and sacrifice on the Civil War’s bloodiest battlefields.

“They must be made of iron!” exclaimed Union Army of the Potomac commander Major General George B. McClellan upon observing the fighting prowess of a brigade of Union soldiers routing Confederate troops at the Battle of South Mountain on September 14, 1862. The bravery and sacrifice of the soldiers of this “Iron Brigade” during the bloodiest battles in the Civil War’s Eastern Theater certainly validated McClellan’s judgment.

Activated in Washington, D.C., in October 1861, the brigade initially was composed of four volunteer infantry regiments – 19th Indiana and 2d, 6th and 7th Wisconsin – and one regular army unit, Battery B, 4th U.S. Artillery. Other volunteer infantry regiments were added later: 24th Michigan in October 1862, and 167th Pennsylvania in mid-July 1863 after horrific losses at the Battle of Gettysburg. The brigade’s first commander was Brigadier General Rufus King but its most famous one was Brigadier General John Gibbon, who led the unit from May-November 1862 and was in command when it earned its famous Iron Brigade nickname.

The unit also had another nickname: the “Black Hat Brigade.” Although nearly all other Army of the Potomac soldiers preferred wearing the more comfortable kepi, members of the Iron Brigade wore the black, high-crowned, broadbrimmed Model 1858 “Hardee” dress hat. Confederate opponents quickly learned to identify the men of this hard-fighting brigade through their distinctive headgear and called them “those damned Black Hats!”

During the war, the Iron Brigade was assigned to various Army of the Potomac corps (I, II and III corps), yet its soldiers were proudest of their assignment and official designation from February 1863: 1st Brigade, 1st Division, I Corps. The unit fought in several notable battles and campaigns during the war, including Second Bull Run (August 1862), Antietam (September 1862), Fredericksburg (December 1862), Chancellorsville (May 1863), Gettysburg (July 1863), the Virginia Campaign (May-June 1864), the Siege of Petersburg (June 1864-March 1865), and Appomattox (April 1865).

While the brigade’s soldiers always fought valiantly, their most desperate combat and bloodiest sacrifice was at Gettysburg, where the unit suffered a 60 percent casualty rate when 1,153 of its 1,885 men were killed or wounded. The brigade’s 2d Wisconsin and 24th Michigan volunteer infantry regiments were particularly hard hit, suffering casualty rates of 77 percent and 80 percent, respectively.

No other soldiers of the Army of the Potomac contributed more to Union victory in the Civil War than did the Great Warriors of the Iron Brigade.


Jerry D. Morelock, PhD, “Armchair General” Editor in Chief.

Originally published in the January 2015 issue of Armchair General.

Share This Article

Citation information

Jerry D. Morelock (6/23/2024) Union Iron Brigade, 1861-65. HistoryNet Retrieved from
"Union Iron Brigade, 1861-65."Jerry D. Morelock - 6/23/2024,
Jerry D. Morelock 2/10/2017 Union Iron Brigade, 1861-65., viewed 6/23/2024,<>
Jerry D. Morelock - Union Iron Brigade, 1861-65. [Internet]. [Accessed 6/23/2024]. Available from:
Jerry D. Morelock. "Union Iron Brigade, 1861-65." Jerry D. Morelock - Accessed 6/23/2024.
"Union Iron Brigade, 1861-65." Jerry D. Morelock [Online]. Available: [Accessed: 6/23/2024]