United States Armies in the EastDepartment of Pennsylvania

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Commanded by Major General Robert Patterson (to July 25)
Major General John A. Dix

The Department of Pennsylvania merged with the Department of Maryland on July 25. General Order #46 honorably discharged Generals Patterson and Cadwallader at the end of their terms of service on July 27th, and almost all of the troops of Patterson’s army mustered out at that time. Thus General Dix and his troops from Maryland (which became known as Dix’s Division) became the Department of Pennsylvania.

1st Division Brig. Gen. George Cadwallader
1st Brigade Col. George H. Thomas  dissolved 7/25, regiments mustered out
3rd Brigade Brig. Gen. A. S. Williams  dissolved 7/22, regiments mustered out
4th Brigade Col. J. C. Longenecker  dissolved 7/21, regiments mustered out
2nd Division Maj. Gen. William H. Keim
2nd Brigade Brig. Gen. G. C. Wynkoop  dissolved 7/23, regiments mustered out
5th Brigade Brig. Gen. J. S. Negley  dissolved 7/23, regiments mustered out
6th Brigade Col. J. J. Abercrombie  dissolved 7/21, regiments mustered out
3rd Division Major General C. P. Sandford  created 6/1
7th Brigade Col. C. P. Stone  to Dept. Shenandoah, 3rd Brig.
8th Brigade Col. Schwartzwalder
Col. D. Butterfield
 dissolved 7/25, regiments mustered out
11th Indiana Infantry Regiment  Colonel Lew Wallace from Cumberland, Md. 7/8
to Indianapolis for muster out 7/29
1st United States Artillery, Battery E from Fort Hamilton, New York 6/3
1st United States Artillery, Battery H from Fort Hamilton, New York 6/3

After July 25

Dix’s Division
1st Delaware Militia Colonel Henry H. Lockwood
6th Massachusetts Infantry Regiment Colonel Edward F. Jones returned to Mass. to muster out 7/29
3rd New York Infantry Regiment Lt. Colonel Samuel M. Alford from Dept. of VA 7/30
4th New York Infantry Regiment Colonel Alfred W. Taylor from Dept. of VA 7/25
5th New York Infantry Regiment Colonel C. Schwartzwaelder from Dept. of VA 7/26
6th New York Militia Regiment Colonel Joseph Pinckney returned to New York 7/29
13th New York State Militia Colonel Abel Smith returned to New York 7/31
20th New York State Militia Colonel George W. Pratt returned to New York 7/31
1st Pennsylvania Reserves Colonel R. Biddle Roberts from Harrisburg 7/22
12th Pennsylvania Infantry Regiment Colonel David Campbell
18th Pennsylvania Infantry Regiment Colonel William D. Lewis  to Philadelphia 7/29 to muster out
19th Pennsylvania Infantry Regiment Colonel Peter Lyle
22nd Pennsylvania Infantry Regiment Colonel Turner G. Morehead
Cook’s Boston, Ma. Battery
2nd United States Artillery, Battery I  at Fort McHenry