The Black Hats: The Iron Brigade of Wisconsin and Michigan

The Iron Brigade wore the wrong hats on purpose.

Most Union volunteers wore the soft, low forage cap. The regiments that became the Iron Brigade wore the tall black felt dress hat of the regular army — the 1858 Hardee hat — because their first brigade commander, John Gibbon, a West Point regular, requisitioned them and made his Western volunteers look and drill like regulars. On a battlefield of blue forage caps, the black hats marked the brigade out. Friend and enemy alike learned to read them at a distance.

The name came at South Mountain, Maryland, on September 14, 1862. The brigade attacked uphill against Confederate troops holding the mountain gaps and pushed them off. Watching the assault, a senior Union officer is said to have asked who those men were, and on being told, remarked that they must be made of iron. The exact words and the exact speaker vary by account. What does not vary is that the brigade walked off South Mountain as the Iron Brigade and carried the name for the rest of the war.

It was the only all-Western brigade in the Army of the Potomac — an army otherwise built from Eastern regiments. Three Wisconsin regiments, one from Indiana, one from Michigan. This series has already told the story of the Hoosier regiment, the 19th Indiana, broken on the first day at Gettysburg. This entry is the rest of the brigade: the Wisconsin and Michigan men who wore the black hats, earned the name, and paid what the name cost.

The only Western brigade

When the brigade was formed in the fall of 1861, it was built from the 2nd, 6th, and 7th Wisconsin and the 19th Indiana. The 24th Michigan joined in October 1862, after Antietam, and was at first resented — a fresh regiment slotted in among veterans to replace the brigade's dead — until it proved itself in the line. Battery B, 4th U.S. Artillery, served alongside the brigade closely enough to be counted part of it.

“Western” meant something specific in the Army of the Potomac. The army was overwhelmingly raised from the Eastern states, and the men of Wisconsin, Indiana, and Michigan knew they were the outliers in it — farm-country volunteers from newer states, many of them the sons of recent settlers, conscious of being watched by Easterners who did not expect much of them. That self-consciousness hardened into pride, and the pride into a brigade identity. The black hats made them visible; the open question was what the visibility would come to mean.

John Gibbon drilled them without mercy through the winter of 1861–62. The black hats were part of that. Gibbon wanted his Western volunteers to think of themselves as the equals of regulars, and he dressed them to match. The men complained about the hats, and then — as the war made his point for him — stopped complaining and started wearing them as a badge.

Gibbon himself was a study in what the war did to families. Born in Philadelphia, raised in North Carolina, a West Point graduate and career artillerist, he stayed with the United States while three of his brothers went with the Confederacy. He led the brigade until his promotion in late 1862, but the discipline he stamped on it outlasted his command. What he left behind was a brigade that thought of itself as Western, as professional, and as something to be measured against the regular army — a self-image that would carry it into fights that broke other units.

The brigade's first major fight was at Brawner's Farm, near Gainesville, Virginia, on the evening of August 28, 1862, at the opening of the Second Bull Run campaign. It was a stand-up firefight at close range against veteran troops of Stonewall Jackson's command. Neither side maneuvered; neither side broke. The lines stood in the open and fired into each other until dark. The brigade lost heavily and held its ground. The men who came through Brawner's Farm understood something about themselves, and about the brigade, that they had not known the day before.

Earning the name

South Mountain, three weeks later, is where the reputation became a name. The brigade went up the slope at Turner's Gap in the late afternoon, drove the Confederate defenders from wall and woodlot, and held the high ground into the night. The fight cost the brigade several hundred men. It also cost it nothing in cohesion — the brigade that reached the top of the mountain was still a brigade.

Three days after that came Antietam. On the morning of September 17, 1862, the Iron Brigade went into the fight at the northern end of the field — through the Cornfield and along the Hagerstown Pike, in some of the most concentrated killing of the entire war. The Cornfield changed hands repeatedly that morning; the men who fought there described it afterward as a place where the standing corn was cut down by gunfire as cleanly as if by a scythe. The brigade was badly cut up. It was after Antietam, with the ranks thinned, that the 24th Michigan was sent up to fill them — and had to earn its place among veterans who had just come through the worst single day of the war.

On the name.

The "made of iron" remark is most often attributed to General George B. McClellan watching the South Mountain assault, and sometimes to other senior officers present. The brigade's own veterans disagreed on the wording in their later accounts. The series records it as earned at South Mountain, September 14, 1862, without claiming a single definitive sentence — the deed is documented; the exact quotation is not.

July 1, 1863

The brigade's defining day was also very nearly its last as the organization it had been.

On the morning of July 1, 1863, the Iron Brigade was rushed forward through the town of Gettysburg to McPherson's Ridge and the woodlot on it — Herbst Woods — west of town, where Union cavalry was buying time against the leading edge of the Confederate army. The 2nd Wisconsin was among the first infantry of the Army of the Potomac into the fight. In the woods, the brigade drove back the Confederate attack and captured a large part of it, including Brigadier General James J. Archer — the first Confederate general officer taken prisoner since Robert E. Lee had assumed command of the Army of Northern Virginia.

The fighting in Herbst Woods cost the Union army one of its best officers within the first hour. Major General John F. Reynolds — commanding the I Corps, and the senior Union officer on the field that morning — was killed by a bullet near the brigade's position as he brought the infantry up. He was the highest-ranking soldier on either side to die at Gettysburg. The brigade he had hurried into the woods would spend the rest of the day proving the ground had been worth a corps commander's life.

To the north, the 6th Wisconsin, with two Eastern regiments, charged an unfinished railroad cut and captured hundreds of Confederates trapped in it. Rufus Dawes, who commanded the 6th that day, left one of the clearest first-hand accounts of the action that exists.

Then the weight of the Confederate advance came down on McPherson's Ridge in earnest, and the brigade spent the rest of the day being destroyed in place. It did not run. It gave ground slowly, a line at a time, back through the town to Cemetery Hill, and what reached Cemetery Hill that evening was a fraction of what had gone into Herbst Woods that morning. The ridge bought the Army of the Potomac the time it needed to hold the high ground south of Gettysburg. The brigade paid for that time at a rate few units in the war ever matched.

The arithmetic of iron

The numbers are the plainest way to say what July 1 did to the brigade.

The Iron Brigade went into Gettysburg with roughly 1,800 men. It lost on the order of 1,150 to 1,200 of them — close to two-thirds — the great majority on the first day. The 24th Michigan took the heaviest loss of any regiment in the brigade: it went into Herbst Woods with about 496 officers and men and lost roughly 360, near three-quarters, with color-bearer after color-bearer shot down carrying the flag. The 2nd Wisconsin, already worn small by two years of hard service, was very nearly wiped out.

The Iron Brigade earned its name for not breaking. Not breaking is what nearly destroyed it.

In Regimental Losses in the American Civil War, the 1889 statistical study that is still the authority on the subject, William F. Fox identified the Iron Brigade as having sustained the highest percentage of battle deaths of any brigade in the Union Army. The 2nd Wisconsin sits at the top of his regimental list for the same measure — it lost a larger share of its men to battle than any other regiment in Union service.

After Gettysburg the brigade was rebuilt. Non-Western regiments were added to bring it back to strength; the 2nd Wisconsin, worn down past the point of a viable regiment, was eventually mustered out and its surviving men reassigned. The all-Western character was gone. The reconstituted brigade served on — through the Wilderness and Spotsylvania in the 1864 Overland Campaign, through the Petersburg siege, to the end of the war — with Battery B alongside it much of the way. But the brigade that fought after Gettysburg was a different organization wearing an older name.

What the black hats cost

The Wisconsin and Michigan dead of the Iron Brigade lie where the war put them — many in the Soldiers' National Cemetery at Gettysburg, on the ground their stand helped hold; others in National Cemeteries further south, from the campaigns the rebuilt brigade fought afterward.

This is the third entry in a standing series on the citizen-soldier Union. The first counted Indiana's regiments, including the 19th Indiana — the brigade's Hoosier regiment, broken in the same woods on the same morning. The second followed the 54th Massachusetts and the United States Colored Troops. The Iron Brigade belongs in that company: a unit that became famous for a quality — not breaking — and then had that exact quality spend it down to a fraction in a single morning's work on a ridge west of a Pennsylvania town.

The dead earn the page. The black hats earned it at South Mountain, and then the brigade was handed the bill at Gettysburg and paid it in full.

Sources

William F. Fox, Regimental Losses in the American Civil War, 1861–1865 (Albany, NY: Albany Publishing Company, 1889). The standard statistical authority on Union unit casualties.
Rufus R. Dawes, Service with the Sixth Wisconsin Volunteers (Marietta, OH: E. R. Alderman & Sons, 1890). Primary memoir by the officer who commanded the 6th Wisconsin at the Railroad Cut.
Alan T. Nolan, The Iron Brigade: A Military History (New York: Macmillan, 1961; later reprints). The standard modern history of the brigade.
Lance J. Herdegen, The Iron Brigade in Civil War and Memory (El Dorado Hills, CA: Savas Beatie, 2012).
U.S. War Department, The War of the Rebellion: Official Records of the Union and Confederate Armies, Series I, Vol. XXVII — reports on the first day at Gettysburg. (Cited as “OR.”)
Frederick H. Dyer, A Compendium of the War of the Rebellion (Des Moines: Dyer Publishing, 1908). Regimental service histories.
National Park Service, Gettysburg National Military Park, McPherson's Ridge and Railroad Cut interpretive resources, nps.gov/gett (accessed 2026-05-14).