Union Irish Heroes at the Battle of Gettysburg

By Dennis Keating
The Cleveland Civil War Roundtable
Copyright © 2023, All Rights Reserved

Editor’s note: This article was originally published in The Charger in November 2023.


Many Irish Americans in the Army of the Potomac fought Robert E. Lee’s invading Army of Northern Virginia at Gettysburg July 1-3, 1863. While the Irish Brigade is best known, there were others who are also worthy of recognition for their heroism. Three of these men died on the field. This article is a day-by-day account both of individuals and of units.

Day One

Tom Devin and William Gamble

As A.P. Hill’s Third Corps of Lee’s army approached Gettysburg from Cashtown in the west, John Buford’s Union First Cavalry Division (two brigades) awaited them. Buford was sent to Gettysburg on June 30 to scout for Confederates. He learned of Lee’s approach and so informed John Reynolds, commander of both the left wing of the army and of the First Corps, and the closest of now army commander George Meade’s forces to Gettysburg.

The next morning, Henry Heth’s Division led a reconnaissance toward Gettysburg. Expecting only to encounter local militia, instead it came up against Buford’s dismounted cavalry and horse artillery defending McPherson’s Ridge with a skirmish line on Herr’s Ridge. Ignoring Lee’s order not to bring on a general engagement until Lee’s scattered army was concentrated, Heth attacked Buford’s Division of about 3,000. Two of Buford’s brigade commanders were Irish: Tom Devin, who was known as “Buford’s Hard Hitter,” and William Gamble.

Thomas Devin

Devin was the child of Irish immigrants and was born in 1822 in New York City. He became the colonel of the 6th New York Volunteer Cavalry and saw action at Antietam, Chancellorsville, and Brandy Station. Gamble was born in Duross, Lisnarick, County Fermanagh, Ireland in 1818. He served in the British army before emigrating to the United States in 1838. He joined the U.S. Army and served in the Seminole Wars before working as a civil engineer in Chicago. Gamble was wounded in McClellan’s Peninsula Campaign.

William Gamble

These two brigade commanders and John Buford were Gettysburg heroes, holding off Heth’s attack until Reynolds (killed soon after his arrival) and his First Corps arrived to confront the attacking Confederates. Buford’s cavalry was withdrawn on July 2 and did not participate in the July 3 cavalry battle against Jeb Stuart’s cavalry.

Devin served in Phil Sheridan’s 1864 Shenandoah Valley Campaign, where he was wounded. He served in the postwar cavalry on the western frontier and was the colonel of the 3rd U.S. Cavalry when he died in 1878. After Gettysburg, Gamble was involved in the defense of Washington City. During this time, he was the commander of the 8th Illinois Cavalry, and a unit of his regiment captured Thomas Harney of the Confederate Torpedo Bureau on April 10, 1865 en route to Washington City to try to kill President Abraham Lincoln and other high-ranking federal officials with bombs. Serving postwar with the 8th U.S. Cavalry, Gamble died of cholera in 1866 in Nicaragua en route to the command of the Presidio in San Francisco.

Day Two

The Irish Brigade

Patrick Kelly

The best-known Irish unit in the Army of the Potomac was the Irish Brigade, originally from New York (69th, 63rd, and 88th New York Regiments) and later joined by the 28th Massachusetts and the 116th Pennsylvania Regiments. Originally led by Michael Corcoran and then by Thomas Meagher, the Irish Brigade was commanded at Gettysburg by Patrick Kelly, colonel of the 88th New York. Kelly was born in Castle Hackett, County Galway, Ireland in 1821 and emigrated to New York City in 1850. At Gettysburg, the 88th was commanded by 22-year-old Captain Denis Burke from County Cork, Ireland, who had been wounded at the Battles of Fredericksburg and Chancellorsville.

Denis Burke

Designated the Second Brigade of John Caldwell’s First Division of Hancock’s Second Corps, the Irish Brigade, much depleted by its heavy casualties at the Battles of Antietam and Fredericksburg, went into battle at Gettysburg with 530 men. Just before the brigade was ordered forward, while Daniel Sickle’s Third Corps was retreating, the Irish Brigade’s chaplain, Father William Corby, memorably mounted a rock and gave mass absolution to its kneeling members.

The Irish Brigade deployed into the Wheatfield and advanced on its Stony Hill, where it was met by the South Carolinians of Joseph Kershaw’s Brigade. With the addition of two other Confederate brigades, Caldwell’s troops were driven back. The Irish Brigade suffered 202 casualties. The commanders of the 63rd New York (Lieutenant Colonel Richard Bentley from County Cavan, Ireland) and the 69th New York (Captain Richard Moroney) were both wounded. Kelly, the Irish Brigade’s commander at Gettysburg, was killed on June 16, 1864 in the Union assault on Petersburg. Moroney was wounded again in Virginia in October 1864. Colonel Richard Byrnes, commander of the 28th Massachusetts from County Cavan, Ireland, was killed at the Battle of Cold Harbor on June 3,1864. Colonel St. Clair Mulholland, commander of the 116th Pennsylvania, was born in Kisburn, County Antrim, Ireland. He won the Medal of Honor for his actions at the Battle of Chancellorsville. He was previously wounded in the assault on Marye’s Heights at the Battle of Fredericksburg. Mulholland led his small unit in Grant’s 1864 Overland Campaign, where he was wounded three more times (at the Battles of the Wilderness, Spotsylvania Court House, and Cold Harbor).

The 126 survivors of the Irish Brigade returned to the Gettysburg battlefield on July 2, 1888 to celebrate the dedication of the New York Irish Brigade Monument (ironically sculpted by a Confederate veteran who fought at Gettysburg with the artillery of Early’s Division of Ewell’s Corps). The side of the monument has a plaque honoring James McKay Rorty’s New York Battery (which is discussed below). The126 survivors were addressed that day by Father Corby, who died in 1897. A monument to Corby, which was dedicated on October 29, 1910, was placed where he gave absolution to the Irish Brigade. In 1890, a Notre Dame University student immortalized Corby in his famous painting, Absolution Under Fire, which hangs in the Art Museum at Notre Dame University.

The 28th Massachusetts Monument was given to the Gettysburg Battlefield Association on “Massachusetts Day,” July 2, 1886. The 116th Pennsylvania Monument was dedicated on September 11, 1889.

Absolution Under Fire

Paddy O’Rorke

Patrick O’Rorke

Patrick (Paddy) O’Rorke was born in County Cavan, Ireland in March 1837. When he was one year old, his family emigrated to Rochester, New York. After his father’s death, he became a marble cutter to support his family. He enrolled at West Point and graduated first in his class in 1861.

O’Rorke participated in the First Battle of Bull Run and then in battles along the southern Atlantic coast. In September 1862, O’Rorke became commander of the 140th New York. He led his regiment at the Battle of Fredericksburg, but at the Battle of Chancellorsville he temporarily commanded a brigade (which included the 140th New York).

At Gettysburg, the 140th New York was in the brigade commanded by Strong Vincent (killed in the defense of Little Round Top). A crisis developed when Gouverneur K. Warren realized that Union troops defending Little Round Top were undermanned as James Longstreet’s Confederates were mounting their attack. He saw O’Rorke’s regiment and ordered it to immediately go to the Union defense. O’Rorke led his regiment in their Zouave uniforms into a vacant space in the line, only to be instantly killed. His enraged soldiers killed his killer with 17 shots as they successfully helped to repel the assault of Confederates from Alabama and Texas regiments. The monument to O’Rorke (and the 140th New York) stands where he fell.

John Lonergan

John Lonergan

John Lonergan was born in 1837 in Carrick-On Suir, County Tipperary, Ireland. His family emigrated to the United States in 1848 and settled in Vermont. He enlisted along with an Irish militia called the Emmet Guards in the 13th Vermont and became a captain of its Company A. Part of George Stannard’s Brigade of Abner Doubleday’s Third Division of the First Corps, they successfully battled Confederates in Winfield Scott Hancock’s section on Day 2, and Lonergan received the Medal of Honor for his and his company’s recapture of four Union guns, the capture of two Confederate guns, and also a company of Confederate prisoners. On Day 3, Stannard’s Vermont Brigade (including Lonergan’s 13th Vermont) faced Pickett’s right flank and delivered devastating fire into James Kemper’s Virginia Brigade. A dedicated Fenian, Lonergan participated in the postwar Fenian raids into Canada aimed at liberating Canada from England. He died in 1902.

Buster Kilrain

Kilrain is the only fictional character in Michael Shaara’s novel The Killer Angels. According to his son Jeff Shaara’s novel Gods and Generals, Kilrain was born in Belfast in 1812, enlisted in the Federal army, and was a sergeant before being demoted for assaulting an officer, but was restored to his rank after being mortally wounded during the 20th Maine’s defense of Little Round Top. He was portrayed by Kevin Conway as being close to Joshua Chamberlain, the commander of the 20th Maine, in the 1993 film Gettysburg. This fictional Irish hero was said to be based on the 20th Maine’s Sergeant George Buck. Kilrain is the subject of the song “Dixieland” written by Steve Earle.

Day Three

Among the Irish Heroes of the Union defense against Pickett’s Charge were Colonel Dennis O’Kane, commander of the 69th Pennsylvania, and Captain James McKay Rorty of the 1st New York Light Artillery.

Dennis O’Kane

O’Kane was born in Coleraine, County Londonderry, Ireland. He emigrated to Philadelphia and became a saloon keeper. He became the lieutenant colonel and then colonel of the largely Irish 69th Pennsylvania of the Philadelphia Brigade.

Dennis O’Kane

On July 3, the much-reduced number of 258 soldiers of the 69th were stationed on Cemetery Ridge behind a stone wall near a clump of trees. Pickett’s Charge targeted this position in its attack. As the thousands of Confederates approached, O’Kane mounted the stone wall and addressed the regiment: “Men, the enemy is coming but hold your fire until you see the whites of their eyes. I know that you are as brave as any troops that you will face, but today you are fighting on the soil of your own state, so I expect you to do your duty to the utmost. If any man among you flinches from that duty, I would ask the man next to him to kill him on the spot.”

While nearby New Yorkers fell back as Lewis Armistead’s Virginians came over the stone wall, O’Kane’s Irish held fast and stopped this final Confederate advance. The cost of their defense was 45 killed (including O’Kane, Lieutenant Colonel Martin Tschudy, and four other officers) and 80 wounded. O’Kane died the next morning from his wound. The monument to the 69th Pennsylvania stands at the Angle where O’Kane fell.

Thomas Horan

Thomas Horan

Thomas Horan was born in Ireland in 1839. His family emigrated to New York state in the late1840s. Horan enlisted in Company E of the 72nd New York. At Gettysburg, he won the Medal of Honor by capturing the flag of the Confederate 8th Florida Infantry as it attempted to join Pickett’s Charge. Horan was later wounded at the Battle of the Wilderness. He died in 1902.

James McKay Rorty

James Rorty

James McKay Rorty emigrated from County Donegal, Ireland to the United States in 1857. He enlisted in Company G of the Irish 69th New York and was captured in its retreat at First Bull Run in 1861. He was imprisoned in a Richmond warehouse, but he and two other prisoners escaped and were rescued on September 28 by a Union gunboat on the Potomac River. A devoted Fenian, Rorty was wounded at the Battle of Fredericksburg. At Gettysburg, Captain Rorty commanded Battery B of the 1st New York Artillery. He died as his battery at the Angle engaged Pickett’s Charge, among the nine of his battery killed with another eight wounded.

8th Ohio (Company B: Cleveland’s Hibernian Guards)

Thomas Galwey

On July 3, the 216 men of the 8th Ohio, including those of Company B (Cleveland’s Hibernian Guards), were stationed on the far right flank in front of the Union defense. Faced with the attack of Johnston Pettigrew’s left wing force, this small regiment poured heavy fire into rebel brigades commanded by John Brockenbrough and Joe Davis, capturing many prisoners and some regimental colors. Almost half of the 8th Ohio were casualties. Thomas Francis Galwey recounted, “I myself was hit three times between the opening of the cannonade and the rout of the enemy. The First and Second Sergeants of my company [B] each lost a leg. Old John Burke, who had served twenty-one years in the 18th Royal Irish, of the British Army, before entering ours, also lost the use of a leg. Lelievre, who was an old French sailor, was also crippled in the leg. Wilson was killed outright, as was Corporal Barney McGuire, a brave, humorous fellow, and Private William Brown died before dark.”

A young Irish immigrant, Clevelander Galwey’s wartime experience from his diary can be found in my book Cleveland and the Civil War.


Related link:
The Irish in the Civil War

References (Click on the book titles on this page to purchase from Amazon. Part of the proceeds from any book purchased from Amazon through the CCWRT website is returned to the CCWRT to support its education and preservation programs.)

Baumgartner, Richard A. Buckeye Blood: Ohio at Gettysburg (Blue Acorn Press, 2002)

Boyle, Frank. A Party of Mad Fellows: The Story of the Irish Regiments in the Army of the Potomac (Morningside Bookshop, 1996)

For Erin and America – James McKay Rorty (The Wild Geese, January 19, 2013)

Fox, Walter. Dennis O’Kane and the 69th Pennsylvania Volunteers (Walterfox. WordPress, June 1999)

Galwey, Thomas Francis. The Valiant Hours: Narrative of ‘Captain Brevet,’ an Irish-American in The Army of the Potomac (The Stackpole Company, 1961)

George Buck, 20th Maine (https://killedatgettysburg.org/george-buck/)

Keating, W. Dennis. Cleveland and the Civil War (The History Press, 2022)

Murphy, T. L. Kelly’s Heroes: The Irish Brigade at Gettysburg (Farnsworth House Military Impressions, 1997)

Pfanz, Harry W. Gettysburg: The Second Day (University of North Carolina Press, 1987)

Sears, Stephen W. Gettysburg (Houghton Mifflin, 2003)

The Irish at Gettysburg (The Wild Geese, January 19, 2013)

‘We Thought We Were All Gone’: The 69th Pennsylvania at Gettysburg (Irish American Civil War, July 3, 2011)