United States Armies in the EastDepartment 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