Overview
The 20th Pennsylvania Infantry (Three Months’ Service) was an early-war Union regiment organized in Philadelphia, Pennsylvania. The regiment was primarily composed of veterans from the Scott Legion, a Philadelphia militia unit with roots in the Mexican War. It was mustered into United States service on April 30, 1861, for a term of three months. The regiment served in the Eastern Theater as part of the initial mobilization following the outbreak of the Civil War.
This unit is distinct from any later regiments with similar designations or longer service terms.
Organization & Service
The 20th Pennsylvania Infantry (Three Months’ Service) was organized at Philadelphia and mustered in on April 30, 1861. The regiment was commanded by Colonel William H. Gray, with Lieutenant Colonel George Moore and Major Andrew H. Tippin as principal field officers. Shortly after organization, the regiment was ordered to Chambersburg, Pennsylvania, where it became part of the 3rd Brigade, 1st Division, under Major General Robert Patterson’s command.
In early June 1861, the regiment moved with Patterson’s force to Williamsport, Maryland, and participated in the advance into the Shenandoah Valley. The 20th Pennsylvania took part in the marches to Martinsburg, Bunker Hill, and Charlestown, Virginia (now West Virginia), performing garrison and guard duties. The regiment did not engage in major combat during its service term. On July 24, 1861, the regiment departed for Philadelphia, where it was mustered out of service.
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
- Advance to Chambersburg, Pennsylvania (June 1861)
- March to Williamsport, Maryland
- Operations at Martinsburg, Bunker Hill, and Charlestown, Virginia (June–July 1861)
Casualties
Specific casualty figures for the 20th Pennsylvania Infantry (Three Months’ Service) are not detailed in primary sources. The regiment did not participate in major battles and suffered minimal losses during its brief term of service.
Field Officers & Commanders
- Colonel William H. Gray
- Lieutenant Colonel George Moore
- Major Andrew H. Tippin
Regimental Roster
The full roster of the 20th Pennsylvania Infantry (Three Months’ Service), including officers and enlisted men, is available for genealogical and historical research. This roster provides names, ranks, and additional service details where available.
To view the complete roster, visit the 20th Pennsylvania Infantry (Three Months’ Service) Roster page.
Sources & References
- Official Records of the Union and Confederate Armies, Series I, Vol. 2
- Pennsylvania Adjutant General’s Report, 1861
- Dyer, Frederick H. A Compendium of the War of the Rebellion
- The Union Army, Federal Publishing Company, 1908, Vol. 1