United States Armies in the East > Department of Pennsylvania
April 1861 • to May >
Commanded by Major General Robert Patterson
The Department of Pennsylvania was established on April 19, 1861 under Major General Robert Patterson. It consisted of the states of Pennsylvania, Delaware, and Maryland and the District of Columbia.
On April 27 General Order #12 removed the District of Columbia and the nearby part of Maryland from the Department to become the Department of Washington and the Department of Annapolis.
| Unattached | ||
| 1st Pennsylvania Infantry Regiment | Colonel Samuel Yohe | at Camp Scott near York 4/20 |
| 2nd Pennsylvania Infantry Regiment | Colonel Frederick S. Stumbaugh | at Camp Scott near York 4/21 |
| 3rd Pennsylvania Infantry Regiment | Colonel Francis P. Minier | at Camp Scott near York 4/20 |
| 4th Pennsylvania Infantry Regiment | Colonel John F. Hartranft | at Perryville, Md. (part) & Annapolis (part) 4/23 |
| 5th Pennsylvania Infantry Regiment | Colonel R.P. McDowell | at Perryville, Md. (part) & Annapolis (part) 4/23 |
| 6th Pennsylvania Infantry Regiment | Colonel James Nagle | at Philadelphia 4/22 |
| 7th Pennsylvania Infantry Regiment | Colonel William I. Irwin | from Harrisburg to Chambersburg 4/23 |
| 8th Pennsylvania Infantry Regiment | Colonel A.H. Emley | from Harrisburg |
| 9th Pennsylvania Infantry Regiment | Colonel Henry C. Longnecker | at Harrisburg |
| 10th Pennsylvania Infantry Regiment | Colonel Sullivan A. Meredith | from Harrisburg 5/1 |
| 12th Pennsylvania Infantry Regiment | Colonel David Campbell | from Harrisburg 5/25 |
| 13th Pennsylvania Infantry Regiment | Colonel Thomas A. Rowley | at York 4/26 |
| 14th Pennsylvania Infantry Regiment | Colonel John W. Johnston | mustered in at Harrisburg 4/30 |
| 17th Pennsylvania Infantry Regiment | Colonel Francis E. Patterson | Organized at Philadelphia 4/25 |
| 18th Pennsylvania Infantry Regiment | Colonel William D. Lewis, Jr. | Mustered in at Philadelphia 8/24 |
| 19th Pennsylvania Infantry Regiment | Colonel Peter Lyle | Mustered in at Philadelphia 4/16 – 4/27 |
| 20th Pennsylvania Infantry Regiment | Colonel Wiliam H. Gray | Mustered in at Philadelphia 4/30 |
| 21st Pennsylvania Infantry Regiment | Colonel John F. Ballier | Mustered in at Philadelphia 4/20 |
| 22nd Pennsylvania Infantry Regiment | Colonel Turner G. Morehead | Mustered in at Philadelphia 4/23 |
| 23rd Pennsylvania Infantry Regiment | Colonel Charles P. Dare | at Perryville, Md. 4/21 |