Overview
The 25th Pennsylvania Infantry (Three Months’ Service) was an early-war Union regiment organized in Pennsylvania in April 1861. As an infantry unit, it was among the first to respond to President Lincoln’s call for volunteers following the outbreak of the Civil War. The regiment is notable for its rapid mobilization and for being among the first troops to reach Washington, D.C., at a critical moment when the capital was threatened.
This unit is distinct from later Pennsylvania regiments with similar designations that served longer terms.
Organization & Service
The 25th Pennsylvania Infantry (Three Months’ Service) was composed initially of five companies: the Logan Guards (Lewistown), Allen Guard (Allentown), Washington Artillery and National Light Infantry (Pottsville), and Ringgold Light Artillery (Reading). These companies volunteered immediately after hostilities began and were mustered into U.S. service at Harrisburg on April 18, 1861, for a three-month term. Due to the urgent need for troops in Washington, these companies departed for the capital the same day, prior to the full regimental organization being completed.
Upon passing through Baltimore, the detachment encountered hostile demonstrations but proceeded safely to Washington, D.C., arriving as the first organized troops to reinforce the city. Subsequently, three additional companies were formed, and two more were organized from the surplus of the original five. Companies E, H, and B were assigned to garrison Fort Washington throughout their service. Companies A and C performed guard duty at the Washington arsenal. The remaining five companies joined the Rockville expedition at Poolesville, marched to Williamsport and Martinsburg, and were attached to the 7th Brigade, 3rd Division. The regiment participated in marches to Bunker Hill and Charlestown. The 25th Pennsylvania Infantry (Three Months’ Service) was mustered out at Harrisburg on July 26, 1861.
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
- Defense of Washington, D.C. (April–July 1861)
- Rockville Expedition
- Marches to Williamsport and Martinsburg
- Marches to Bunker Hill and Charlestown
Casualties
Specific casualty figures for the 25th Pennsylvania Infantry (Three Months’ Service) are not detailed in primary sources. The regiment’s service was primarily in garrison and guard duty, with limited combat exposure.
Field Officers & Commanders
- Colonel Henry L. Cake
- Lieutenant Colonel John B. Selheimer
- Major Edward B. Pearson, Jr.
Regimental Roster
The full roster of officers and enlisted men who served in the 25th Pennsylvania Infantry (Three Months’ Service) is available for genealogical and historical research. This roster includes names, ranks, and company assignments as recorded in official state and federal records.
To view the complete roster, visit the 25th 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
- Federal Publishing Company, The Union Army, Vol. 1 (1908)