Overview
The 33rd Pennsylvania Infantry (also known as the 4th Pennsylvania Reserve Infantry) was an infantry regiment from Pennsylvania that served in the Union Army during the American Civil War. Organized at Harrisburg in June 1861 for a three-year term, the regiment was part of the Pennsylvania Reserves division and saw extensive service in the Eastern Theater. The unit was also designated as the 4th Regiment, Pennsylvania Reserve Corps.
The regiment participated in several major campaigns and battles, earning distinction for its actions, particularly during the Peninsula Campaign and at the Battle of Glendale. It mustered out in June 1864, with its veterans and recruits transferred to the 54th Pennsylvania Infantry.
Organization & Service
The 33rd Pennsylvania Infantry (4th Pennsylvania Reserves) was organized at Harrisburg, Pennsylvania, in June 1861 and mustered in for three years’ service. The regiment departed for Baltimore on July 21, 1861, where it remained on duty until late August. It was then ordered to Tennallytown, Maryland, joining the Army of the Potomac as part of the 2nd Brigade, Pennsylvania Reserves Division.
The regiment was present at the Battle of Mechanicsville and was closely engaged at Gaines’ Mill. At the Battle of Glendale (Frayser’s Farm), the 33rd Pennsylvania took part in a fierce bayonet fight, suffering significant losses but holding its position. The regiment was in reserve at Malvern Hill and subsequently participated in the Second Battle of Bull Run, South Mountain, Antietam, and Fredericksburg. After Fredericksburg, the regiment was ordered to the defenses of Washington, D.C., to recuperate and remained there until January 1864.
In early 1864, the regiment participated in the West Virginia campaign. From that point, its service paralleled that of the 32nd Pennsylvania Infantry. On June 17, 1864, the 33rd Pennsylvania Infantry was mustered out at Philadelphia. Veterans and remaining recruits were transferred to the 54th Pennsylvania Infantry.
Research This Regiment Further
If you’d like to explore this unit’s history in more depth, regimental histories and Civil War reference works offer valuable detail.
Engagements & Campaigns
- Baltimore duty (July–August 1861)
- Mechanicsville
- Gaines’ Mill
- Glendale (Frayser’s Farm)
- Malvern Hill (in reserve)
- Second Bull Run
- South Mountain
- Antietam
- Fredericksburg
- Defenses of Washington (winter 1862–1863)
- West Virginia campaign (January 1864)
Casualties
According to available sources, the 33rd Pennsylvania Infantry (4th Pennsylvania Reserves) suffered significant losses, especially at Glendale. Exact figures for killed, wounded, and died of disease are not consistently reported in primary sources. Fox’s Regimental Losses and state reports provide partial data, but comprehensive totals are not available for all categories.
Some details are incomplete in surviving primary sources.
Field Officers & Commanders
- Colonel Robert G. March
- Colonel Albert L. Magilton
- Colonel R. H. Woolworth
- Colonel Thomas F. B. Tapper
- Lieutenant Colonel John F. Gaul
- Lieutenant Colonel Thomas B. F. Tapper
- Lieutenant Colonel Frederick A. Conrad
- Major Robert M. McClure
- Major John Nyce
- Major Enos L. Christman
- Major Frederick A. Conrad
- Major J. W. Shoemaker
Regimental Roster
The full roster of the 33rd Pennsylvania Infantry (4th Pennsylvania Reserves), including officers and enlisted men, is available on the regiment’s roster page. This resource provides names, ranks, and service details valuable for genealogical and historical research.
To view the complete roster, visit the 33rd Pennsylvania Infantry (4th Pennsylvania Reserves) Roster page.
Sources & References
- Official Records of the Union and Confederate Armies, Series I, Volumes XI, XII, XIX, and related correspondence
- Pennsylvania Adjutant General’s Report
- Dyer, Frederick H. “A Compendium of the War of the Rebellion”
- Fox, William F. “Regimental Losses in the American Civil War”
- “The Union Army,” Federal Publishing Company, 1908, Volume 1