United States Army > Army of the Potomac

September 1862 • to October >

Commanded by:
Major General Joseph F. K. Mansfield (mortally wounded September 17)
Brigadier General Alpheus Williams

The Twelfth Corps was transferred from the Army of Virginia, 2nd Corps, on September 12, 1862

First Division

Brigadier General Alpheus S. Williams (^ 9/17)
Brigadier General Samuel W. Crawford (w 9/17)
Brigadier General George Gordon

First Brigade

Brigadier General Samuel W. Crawford (to 9/17)
Colonel J. F. Knipe
5th Connecticut Infantry Regiment Captain Henry W. Daboll
10th Maine Infantry Regiment Colonel George L. Beal (w 9/17)
28th New York Infantry Regiment Captain William H. H. Mapes
46th Pennsylvania Infantry Regiment Colonel Joseph F. Knipe (^ 9/17)
Lieutenant Colonel J.L. Selfridge
124th Pennsylvania Infantry Regiment Colonel Joesph W. Hawley (w 9/17)
Major Isaac L. Haldeman
 from Defences Washington
125th Pennsylvania Infantry Regiment Colonel Jacob Higgins  from Defences Washington
128th Pennsylvania Infantry Regiment Colonel Samuel L. Croasdale (k 9/17)
Lieutenant Colonel William W. Hammersly (w 9/17)
Major Joel B. Wanner
 from Defences Washington

Third Brigade

Brigadier General George H. Gordon (^ 9/17)
Colonel Thomas H. Ruger
20th Connecticut Infantry Regiment Colonel Samuel Ross from Connecticut 9/11
27th Indiana Infantry Regiment Colonel Silas Colgrove
2nd Massachusetts Infantry Regiment Colonel George L. Andrews
13th New Jersey Infantry Regiment Colonel Ezra A. Carman from New Jersey 9/1
107th New York Infantry Regiment Colonel Robert Van Valkenburgh from Defences Washington, Whipple’s Div.
29th Pennsylvania Infantry Regiment Captain Samuel M. Zulich
3rd Wisconsin Infantry Regiment Colonel Thomas H. Ruger (^)

Division Artillery

1st New York Artillery, Battery M Captain George W. Cothran
4th United States Artillery, Battery F Lieutenant Edward D. Muhlenberg

Second Division

Brigadier General George S. Greene

First Brigade

Colonel Charles Candy (to 9/17)
Lieutenant Colonel Hector Tyndale (w 9/17)
Major O. J. Crane (to 9/18)
Colonel Charles Candy
5th Ohio Infantry Regiment Major John Collins
7th Ohio Infantry Regiment Major Orrin J. Crane (^ 9/17)
Captain Frederick A. Seymour
29th Ohio Infantry Regiment Lieutenant Theron S. Winship
66th Ohio Infantry Regiment Lieutenant Colonel Eugene Powell (w 9/17)
28th Pennsylvania Infantry Regiment Major Ario Pardee, Jr.

Second Brigade

Colonel T.B. Van Buren (to 9/15)
Colonel H. J. Stainrook (to 9/17)
Lieutenant Colonel James C. Lane
3rd Maryland Infantry Regiment Lieutenant Colonel Joseph M. Sudsburg
102nd New York Infantry Regiment Lieutenant Colonel James C. Lane (^ 9/17)
109th Pensylvania Infantry Regiment Captain George E. Seymour
111th Pensylvania Infantry Regiment Major Thomas M. Walker (w 9/17)
8th & 12th United States Infantry  to Army HQ 9/17

Third Brigade

Colonel J. A. Tate (to 9/16)
Colonel William B. Goodrich
 (k 9/17)
Lieutenant Colonel Jonathan Austn 
3rd Delaware Infantry Regiment Major Arthur McGinnins (w 9/17)
Captain William J. McKaig
1st District of Columbia Infantry Colonel James A. Tait not present due to sickness and desertion
Purnell Legion (Maryland) Infantry Lieutenant Colonel Benjamin L. Simpson
60th New York Infantry Regiment Lieutenant Colonel Charles R. Brundage
78th New York Infantry Regiment Lieutenant Colonel Jonathan Austin (^ 9/17)
Captain Henry R. Stagg

Division Artillery

16th Indiana Battery from Army Virginia 2 Corps
6th Maine Independent Battery Captain Freeman McGilvery from 3 Corps 1 Div.
Pennsylvania Independent Battery E Captain Joseph M. Knap from Army Virginia 2 Corps 1 Div 
Pennsylvania Independent Battery F Captain Robert B. Hampton from Army Virginia 2 Corps 2 Div