Overview
The 20th Pennsylvania Cavalry (181st Regiment) (Three Months’ Service) was a Union cavalry regiment organized in Pennsylvania during the summer of 1863. The regiment was recruited from the counties of Bucks, Montgomery, Chester, Dauphin, Cumberland, Union, and the city of Philadelphia. It was mustered in response to the emergency created by the Confederate invasion of Pennsylvania in June and July 1863. The regiment served primarily in the Department of the Susquehanna and the Middle Department, performing scouting, picket, and guard duties during the Gettysburg Campaign and its aftermath.
This unit is distinct from the 20th Pennsylvania Cavalry (Six Months’ Service).
Organization & Service
The 20th Pennsylvania Cavalry (Three Months’ Service) was organized at Camp Couch, Harrisburg, in June and July 1863. Seven companies were mustered into United States service for six months, while five companies were organized as emergency militia during the Confederate invasion. The regiment was officially organized in July 1863 under Colonel John E. Wynkoop.
During the Gettysburg Campaign, the regiment operated by detachments, conducting scout and picket duty at the fords of the Susquehanna River and along roads leading toward Carlisle, York, and Marysville. On July 7, 1863, the regiment left Camp Couch and moved to Greencastle, then proceeded to Falling Waters, where it was engaged in picketing the Potomac River for several weeks. The emergency companies subsequently returned to Harrisburg, and their places were filled by men enlisted for six months’ service.
In August 1863, the regiment moved to Sir John’s Run, West Virginia, and was assigned to railroad guard duty toward Winchester. Companies F and I were stationed at Berkeley Springs, D and E at Bloomery Gap, A and H at Great Cacapon Station, and C at Hancock. The remaining five companies were detached for service at Philadelphia, Reading, and Pottsville, and did not rejoin the main regiment until muster out.
In November, the regiment relocated to Springfield, West Virginia. Two companies conducted a reconnaissance nearly 100 miles south, where they engaged and defeated a portion of Imboden’s Confederate command, capturing several prisoners. The regiment was ordered to Harrisburg on December 24, 1863, and was mustered out of service on January 7, 1864.
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
- Gettysburg Campaign (June–July 1863)
- Scout and picket duty along the Susquehanna River, Carlisle, York, and Marysville
- Picket duty at Greencastle and Falling Waters, Maryland
- Railroad guard duty near Winchester, West Virginia
- Reconnaissance and skirmish with Imboden’s command (November 1863)
Casualties
Specific casualty figures for the 20th Pennsylvania Cavalry (Three Months’ Service) are not separately reported in available primary sources. The regiment’s duties were primarily scouting, picket, and guard service, with limited direct combat.
Some details are incomplete in surviving primary sources.
Field Officers & Commanders
- Colonel John E. Wynkoop
- Lieutenant Colonel William Rotch Wister
- Major Samuel W. Comly
- Major J. Harry Thorp
- Major Robert W. Douglass
Regimental Roster
The complete roster of officers and enlisted men who served in the 20th Pennsylvania Cavalry (Three Months’ Service) is available on the regiment’s roster page. This resource provides names, ranks, and additional service details for genealogical and historical research.
To view the full roster, visit the 20th Pennsylvania Cavalry (Three Months’ Service) Roster page.
Sources & References
- Official Records of the Union and Confederate Armies, Series I, Vol. 27, 29, 33
- Pennsylvania Adjutant General’s Report, 1863–1864
- Dyer, Frederick H. Compendium of the War of the Rebellion
- Federal Publishing Company, The Union Army, Vol. 1 (1908)