Peter O'Brien

Capturing Confederate Colors at Waynesboro

Peter O'Brien was an Irish-born Union Army cavalryman and recipient of the United States Medal of Honor whose courage during the American Civil War earned him national recognition. Serving as a private in Company A of the 1st New York Volunteer Cavalry, also known as the Lincoln Cavalry, he distinguished himself at the Battle of Waynesboro, Virginia, on March 2, 1865. During the engagement, O'Brien captured a Confederate flag and took a Confederate officer prisoner, together with the officer's horse and equipment. His actions earned him the Medal of Honor on March 26, 1865.

O'Brien was born around 1842 in Dublin, Ireland. The available historical records do not establish his exact date of birth, family background, education, or early occupation. He later immigrated to the United States and became associated with New York City, where he entered military service during the opening months of the Civil War.

In August 1861, O'Brien enlisted in the Union Army in New York City. He joined Company A of the 1st New York Volunteer Cavalry, a regiment organized under special authorization from President Abraham Lincoln.

The regiment was commonly known as the Lincoln Cavalry and was also identified by the nicknames Carbine Rangers and Sabre Regiment. Its organization began in New York City during the spring of 1861, initially under Colonel Carl Schurz. Colonel Andrew T. McReynolds subsequently assumed command as the regiment completed its organization.

Company A was among the companies recruited principally in New York City. The regiment entered federal service between July and August 1861 and began military operations in the eastern theater.

During the Civil War, the 1st New York Cavalry served with several Union formations, including elements of the Army of the Potomac, the Department of West Virginia, and the Army of the Shenandoah.

Its wartime responsibilities included reconnaissance, mounted patrols, screening movements, and engagements against Confederate cavalry and infantry. The regiment participated in numerous military operations in Virginia, Maryland, Pennsylvania, and West Virginia.

The documented regimental history includes participation in major campaigns and engagements during the war. However, the surviving individual records do not establish O'Brien's presence at every battle involving the regiment. His personal participation at Waynesboro on March 2, 1865, is directly confirmed by his Medal of Honor citation and a contemporary newspaper account.

By the winter of 1864–1865, the Confederate military position in the Shenandoah Valley had deteriorated considerably.

Union cavalry under Major General Philip H. Sheridan had defeated Confederate forces in a succession of engagements during the 1864 Valley Campaign. General Jubal A. Early's remaining troops nevertheless continued to operate in the region.

In late February 1865, Sheridan began another expedition southward through the Shenandoah Valley. His cavalry advanced from Winchester toward Staunton, seeking to destroy Confederate military resources and eliminate the remaining organized resistance.

On March 2, 1865, Union cavalry encountered Early's forces near Waynesboro, Virginia.

The Confederate troops occupied a defensive position west of the town. Sheridan's advancing force included cavalry under Major General George Armstrong Custer, whose division prepared to attack the Confederate line.

The Union assault developed rapidly. Dismounted cavalrymen moved against the Confederate flank while mounted troops advanced along the road, threatening to overwhelm the defenders.

Confederate resistance collapsed as the Union cavalry broke through the position. Large numbers of Confederate soldiers surrendered, while others attempted to escape toward the Blue Ridge Mountains.

It was during this engagement that Private Peter O'Brien performed the actions for which he received the Medal of Honor.

Serving with Company A of the 1st New York Cavalry, O'Brien participated in the advance following the initial attack.

His account of the engagement was preserved in a contemporary newspaper report describing the presentation of captured Confederate flags to the War Department in Washington.

O'Brien explained that the 1st New York Cavalry had been sent forward in support after the 8th New York Cavalry charged along the road. As his unit advanced, he passed General Custer and continued toward the retreating Confederate forces.

During the pursuit, O'Brien encountered an officer of the Confederate 7th Virginia Cavalry.

He captured the officer, together with his horse and military equipment, and sent the prisoner to the rear.

O'Brien also reported taking possession of the officer's revolver, which he handed over to his lieutenant. His account suggests that the captured officer identified himself as Captain Zeke, although the precise name and identity remain uncertain.

In the same contemporary account, O'Brien appeared with a Confederate flag that he believed to be a regimental standard.

His official Medal of Honor citation confirms both achievements: the capture of a Confederate flag and the capture of a Confederate officer with his horse and equipment.

The citation does not identify the regiment to which the flag belonged. Although O'Brien's firsthand account identifies the captured officer's unit as the 7th Virginia Cavalry, that does not independently establish the origin of the flag.

The distinction is important because several Union cavalrymen captured Confederate flags during the Battle of Waynesboro, and the official records attribute separate captures to individual soldiers.

The engagement ended in a decisive Union victory.

Sheridan's forces captured more than 1,500 Confederate soldiers according to the National Park Service's battle summary. General Early and a small number of his staff escaped, but the defeat effectively destroyed his remaining organized force in the Shenandoah Valley.

O'Brien's capture of a Confederate officer and flag formed part of the wider Union success.

Later in March 1865, captured Confederate standards were presented to the War Department in Washington.

A contemporary newspaper account describes a ceremony attended by Secretary of War Edwin M. Stanton, Senator Ira Harris of New York, and several of the Union cavalrymen responsible for capturing enemy flags.

Peter O'Brien was among the soldiers whose actions were described during the proceedings.

The ceremony provided an unusually valuable record of his battlefield achievement because it preserved his own account of the capture rather than relying solely on the brief wording of his official military citation.

Secretary Stanton publicly commended the cavalrymen for their service and announced that their courage would be recognized with the Medal of Honor.

On March 26, 1865, O'Brien received the Medal of Honor for his actions at Waynesboro.

The award recognized his capture of the Confederate flag and the officer, along with the officer's horse and equipment, during the engagement on March 2.

His recognition came only twenty-four days after the battle and shortly before the final collapse of the Confederacy.

The 1st New York Cavalry continued serving during the closing weeks of the Civil War. Its regimental history records participation in the final operations associated with the Appomattox Campaign and the surrender of General Robert E. Lee's Army of Northern Virginia.

The regiment was mustered out of federal service at Alexandria, Virginia, on June 27, 1865.

O'Brien's military service ended in 1865. Although his Medal of Honor action occurred while he held the rank of private, surviving biographical records identify corporal as his highest rank.

After the war, O'Brien eventually settled in Chicago, Illinois.

Details concerning his civilian occupation, marriage, children, and personal activities after military service have not been reliably established. His surviving biographical record remains concentrated on his military service and Medal of Honor recognition.

Peter O'Brien died on September 30, 1898, in Chicago, Illinois, approximately thirty-three years after the end of the Civil War.

He was buried at Rosehill Cemetery in Chicago, where his grave is recorded in Section H, Lot 47, Grave 46841.

His military achievement has been preserved through the United States Army's official Medal of Honor records, the Congressional Medal of Honor Society, and the historical records of New York's Civil War cavalry regiments.

Peter O'Brien is remembered for his actions at the Battle of Waynesboro on March 2, 1865. His capture of a Confederate flag and an enemy officer, together with the officer's horse and equipment, distinguished him during one of the final Union cavalry victories in the Shenandoah Valley. His Medal of Honor remains a lasting tribute to his courage and his service with the Lincoln Cavalry during the American Civil War.