Department of Pennsylvania (American Civil War)
| Department of Pennsylvania | |
|---|---|
Pennsylvania flag
|
|
| Active | April 27 - July 25, 1861 |
| Country |
 United States of America
|
| Branch |
 United States Army
|
| Type | Field Army |
| Engagements | |
| Commanders | |
| Notable commanders |
Robert Patterson |
The Department of Pennsylvania (or General Patterson's Army) was a large military unit in the Union Army at the outset of the American Civil War. Established on April 27, 1861, its territory consisted of Pennsylvania, Delaware, and all of Maryland not embraced in the Department of Annapolis (later renamed Department of Maryland) and the Department of Washington. Its remnants were absorbed into the short-lived Department of the Shenandoah on July 19, 1861, which also absorbed the Department of Maryland on July 25, and on August 24 was merged into the Department of the Potomac.
It was under the command of Major General Robert Patterson, its manpower mainly consisted of three-month troops from the states of Pennsylvania and New York. After achieving a tactical victory at the Battle of Hoke's Run on July 2 and contributing indirectly to the Union disaster at the First Battle of Bull Run on July 21, its unexpired regiments and commanders were absorbed into the Department of the Shenandoah under the command of Major General Nathaniel P. Banks on July 25, 1861.
When President Abraham Lincoln called for 75,000 volunteers in the spring of 1861, the Commonwealth of Pennsylvania produced more than twice its quota. For political reasons the U.S. Secretary of War, Simon Cameron, rejected fifteen regiments for immediate service, and they became known as the 1st through 15th Pennsylvania Reserves. Pennsylvania elected to retain, organize, train and equip them at its own expense.
These fifteen regiments were unavailable either to Patterson in the Shenandoah Valley or to McDowell at First Bull Run. "Within four days after the disaster at Bull's Run, eleven regiments of this fine body of men (armed, drilled, clothed, equipped, and in all respects ready for active service) were in Washington," Governor Andrew G. Curtin reminded the State Legislature.
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Wikipedia