123rd Pennsylvania Infantry

123rd Pennsylvania Infantry
Unit name	123rd Pennsylvania Infantry
Dates	August 1862 – June 1865
Country	United States
Allegiance	Union
Branch	United States Army
Type	Infantry
Size	Regiment
Battles	American Civil War, Battle of Antietam, Battle of Gettysburg, Overland Campaign, Siege of Petersburg

123rd Pennsylvania Infantry was an infantry regiment that served in the Union Army during the American Civil War. Mustered in during 1862, the regiment participated in major campaigns in the Eastern Theater, including engagements in Maryland, Virginia, and Pennsylvania. The unit attracted volunteers from central and eastern Pennsylvania and served until the conclusion of the war in 1865.

Formation and Organization

The regiment was raised during the aftermath of the Second Battle of Bull Run and the Confederate invasion that precipitated the Maryland Campaign, drawing recruits from counties such as Centre County, Pennsylvania, Clearfield County, Pennsylvania, and Huntingdon County, Pennsylvania. Officers received commissions under authority of the Commonwealth of Pennsylvania and reported to the Department of the Potomac before assignment to brigades within the II Corps and later the VI Corps of the Army of the Potomac. Training and initial encampments linked the regiment with facilities near Camp Curtin and staging areas at Harrisburg, Pennsylvania and Philadelphia, Pennsylvania.

Service History

Following organization and muster, the regiment moved to defend the approaches to Washington, D.C. and then took part in movements during the Maryland Campaign, arriving in the vicinity of Antietam Creek shortly after the Battle of Antietam. Through 1863 the regiment was engaged in operations during the Chancellorsville Campaign, the Gettysburg Campaign, and in skirmishes along the Rappahannock River. In 1864 the regiment joined the Overland Campaign under Ulysses S. Grant and fought in protracted operations leading into the Siege of Petersburg, conducting trench warfare and assaults linked to actions at Spotsylvania Court House and Cold Harbor. In 1865 it participated in the final Appomattox Campaign and was present for movements culminating in the surrender at Appomattox Court House, after which it marched to Washington, D.C. for the Grand Review.

Engagements and Battles

The regiment’s recorded actions included presence or combat roles in major and minor operations across the Eastern Theater. Early involvement associated it with the aftermath of Battle of Antietam, and it later fought at Battle of Gettysburg during the critical three-day battle that halted the Gettysburg Campaign. During 1864-1865 the regiment engaged in the Overland Campaign battles such as Battle of the Wilderness, Battle of Spotsylvania Court House, and Battle of Cold Harbor, then entered siege operations during the Siege of Petersburg. Elements of the regiment were involved in assaults on Confederate fortifications and in significance-supporting actions during the Appomattox Campaign, contributing to the collapse of General Robert E. Lee’s Army of Northern Virginia.

Commanders and Notable Personnel

Regimental leadership included colonels and field officers commissioned by the Commonwealth of Pennsylvania, who coordinated with higher commanders such as George G. Meade of the Army of the Potomac and later with elements under Ulysses S. Grant during joint operations. Company officers often came from local civic leaders and veterans of prior service who connected the regiment to communities represented in the Pennsylvania militia tradition. Notable enlisted men and junior officers earned recognition through brevet promotions, mentions in reports by brigade and division commanders, and participation in actions that drew attention from corps commanders like Winfield Scott Hancock and Philip H. Sheridan.

Casualties and Losses

Throughout its term of service the regiment suffered casualties from combat, disease, and attrition typical of Eastern Theater units. Losses included men killed or mortally wounded in assaults and defensive actions at engagements such as Gettysburg and during assaults on Petersburg’s fortifications, as well as deaths from illnesses during encampments and marches. Wounded soldiers were treated in Civil War military hospitals near front-line railheads and in cities such as Frederick, Maryland and Williamsport, Maryland, and many invalided soldiers were sent to convalescent facilities in Philadelphia, Pennsylvania and Baltimore, Maryland.

Legacy and Commemoration

After mustering out, veterans formed local Grand Army of the Republic posts and participated in reunions and memorial activities, contributing to preservation efforts at sites like Gettysburg National Military Park and Antietam National Battlefield. Monuments and regimental markers erected on battlefields and in hometowns commemorate service and sacrifice, often appearing in rolls and rosters compiled by Pennsylvania State Archives and local historical societies. The regiment’s service is referenced in histories of the Army of the Potomac, studies of the Overland Campaign, and in commemorations associated with Memorial Day observances conducted by veterans’ organizations and municipal associations.

Category:Units and formations of the Union Army from Pennsylvania Category:Military units and formations established in 1862 Category:Military units and formations disestablished in 1865