Union order of battle

As I stated a few weeks ago, here is the Union order of battle for South Mountain.

Army of the Potomac

Major General George B. McClellan

Left Wing

Major General Ambrose Burnside

1st Corps

Major General Joseph Hooker

1st Division

Brigadier General John Hatch

1st Brigade, Colonel Walter Phelps, Jr.

2nd US Sharpshooters,Colonel Henry A.V. Post

22nd New York, Lt. Colonel John McKie

24th New York, Captain John D. O'Brian

30th New York, Colonel William M. Searing

84th New York/14th Brooklyn, Major William H. DeBevoise

2nd Brigade, Brigadier General Abner Doubleday

7th Indiana, Major Ira G. Grover

56th Pennsylvania, Lt. Colonel John W. Hofmann

76th New York, Colonel William P. Wainwright

95th New York, Major Edward Pye

3rd Brigade, Brigadier General Marsena Patrick

21st New York, Colonel William F. Rodgers

23rd New York, Colonel Henry C. Hoffman

35th New York, Colonel Newton B. Lord

80th New York, Lt. Colonel Theodore B. Gates

4th Brigade, Brigadier General John Gibbon

2nd Wisconsin, Colonel Lucius Fairchild

6th Wisconsin, Lt. Colonel Edward S. Bragg

7th Wisconsin, Captain John Callis

19th Indiana, Colonel Solomon Meredith

1st Division Artillery, Captain J. Albert Moore

Battery B, 4th United States Light Artillery, Captain Joseph B. Campbell

2nd Division

Brigadier General James Ricketts

1st Brigade, Brigadier General Abram Duryea

97th New York, Major Charles Northrup

104th New York, Major Lewis C. Skinner

107th Pennsylvania, Captain James MacThomson

2nd Brigade, Colonel William Henry Christian

26th New York, Colonel Richard H. Richardson

88th Pennsylvania, Lt. Colonel George W. Gile

90th Pennsylvania, Colonel Peter Lyle

3rd Brigade, Brigadier General George L. Hartsuff

12th Massachusetts, Major Elisha Burbank

13th Massachusetts, Major J. Parker Gould

11th Pennsylvania, Colonel Richard Coulter

3rd Division

Brigadier General George G. Meade

1st Brigade, Brigadier General Truman Seymour

1st Pennslvania Reserves (30th P.V.I.), Colonel R. Biddle Roberts

2nd Pennsylvania Reserves (31st P.V.I.), Captain James Byrnes

5th Pennslvania Reserves (34th P.V.I.), Colonel Joseph W. Fisher

6th Pennsylvania Reserves (35th P.V.I.), Colonel William Sinclair

13th Pennsylvania Reserves (42nd P.V.I.), Colonel Hugh W. McNeil

2nd Brigade, Colonel Henry C. Bolinger

3rd Pennsylvania Reserve, Lt. Colonel John C. Clark

4th Pennsylvania Reserve, Major John Nyce

7th Pennsylvania Reserve, Colonel Henry C. Bollinger

8th Pennsylvania Reserve, Major Silas M. Baily

3rd Brigade, Colonel Thomas F. Gallagher

9th Pennsylvania Reserves, Lt. Colonel Robert Anderson

10th Pennsylvania Reserves, Lt. Colonel Adoniram J. Warner

11th Pennsylvania Reserves, Lt. Colonel Samuel M. Jackson

12th Pennsylvania Reserces, Captain Richard Gustin

9th Corps

Major General Jesse L. Reno

Kanawha Division

Major General Jacob Cox

1st Brigade, Colonel Eliakim Scammon

12th Ohio, Colonel Carr B. White

23rd Ohio, Lt. Colonel Rutherford B. Hayes

30th Ohio, Colonel Hugh B. Ewing

Ohio Light Artillery, First Battery, Captain James R. McMullin

2nd Brigade, Colonel George Crook

11th Ohio, Lt. Colonel Augustus H. Coleman

28th Ohio, Lt. Colonel Gottfried Becker

36th Ohio, Lt. Colonel Melvin Clarke

Kentucky Light Artillery, Simmond's Battery, Captain Seth J. Simmonds

1st Division

Brigadier General Orlando B. Willcox

1st Brigade, Colonel Benjamin Christ

17th Michigan, Colonel William H. Withington

50th Pennsylvania, Major Edward Overton, Jr.

79th New York, Lt. Colonel David Morrison

2nd Brigade, Colonel Thomas Welch

8th Michigan, Lt. Colonel Frank Graves

45th Pennsylvania, Lt. Colonel John I. Curtin

46th New York, Lt. Colonel Joseph Gerhardt

100th Pennsylvania, Lt. Colonel David A. Leckey

1st Division Artllery, commander unknown

Massachusetts Light Artillery, 8th Battery, Captain Asa Cook

2nd Division

Brigadier General Samuel D. Sturgis

1st Brigade, Brigadier General James Nagle

2nd Maryland, Lt. Colonel J. Eugene Duryea

48th Pennsylvania, Lt. Colonel Joshua K. Sigfried

6th New Hampshire, Colonel Simon G. Griffin

9th New Hampshire, Colonel Enoch Q. Fellows

2nd Brigade, Brigadier General Edward Ferrero

21st Massachusetts, Colonel William S. Clark

35th Massachusetts, Colonel Edward A. Wild

51st New York, Colonel Robert Potter

51st Pennsylvania, Colonel John F. Hartranft

2nd Division Artillery, commander unknown

4th United States Artllery, Battery E, Captain Joseph Clark, Jr.

Pennsylvania Light Artillery, Battery D, Captain George Durell

3rd Division

Brigadier General Issac Rodman

1st Brigade, Colonel Harrison Fairchild

9th New York, Lt. Colonel Edgar Kimball

89th New York, Major Edward Jardine

103rd New York, Major Benjamin Ringold

2nd Brigade, Colonel Edward Harland

4th Rhode Island, Colonel William H. P. Steere

11th Conneticutt, Colonel Henry Kingsbury

16th Conneticutt, Colonel Francis Beach

6th Corps

Major General William B. Franklin

1st Division

Major General Henry Slocum

1st Brigade, Colonel Alfred Torbert

1st New Jersey, Lt. Colonel Mark W. Coliet

2nd New Jersey, Colonel Samuel Buck

3rd New Jersey, Colonel Henry Brown

4th New Jersey, Colonel William B. Hatch

2nd Brigade, Colonel Joseph J. Bartlett

5th Maine, Colonel Nathaniel J. Jackson

16th New York, Lt. Colonel Joel Seaver

27th New York, Lt. Colonel Alexander D. Adams

121st New York, Colonel Richard H. Franchot

96th Pennsylvania, Colonel Henry L. Cake

3rd Brigade, Brigadier General John Newton

18th New York, Lt. Colonel George R. Myers

31st New York, Lt. Colonel Francis E. Pinto

32nd New York, Colonel Roderick N. Matheson

95th Pennsylvania, Lt. Colonel Gustavus W. Town

1st Division Artillery, Captain Emory Upton

Battery A, Maryland Light Artillery, Captain John W. Wolcott

1st Battery (A), Massachusetts Light Artillery, Captain Josiah Porter

1st Battery (A), New Jersey Light Artillery, Captain William Hexamer

Battery D, 2nd United States Artillery, Lt. Edward B. Williston

2nd Division

Major General William F. Smith

1st Brigade, Brigadier General Winfield S. Hancock

5th Wisconsin, Colonel Amasa Cobb

6th Maine, Colonel Hiram Burnham

43rd New York, Major John Wilson

137th Pennsylvania, Colonel Henry M. Bossert

2nd Brigade, Brigadier General William T.H. Brooks

2nd Vermont, Major James H. Walbridge

4th Vermont, Lt. Colonel Charles Stoughton

5th Vermont, Colonel Lewis A. Grant

6th Vermont, Major Oscar Tuttle

3rd Brigade, Colonel William Howard Irwin

7th Maine, Major Thomas Hyde

20th New York, Colonel Ernest Von Vegesack

33rd New York, Lt. Colonel Joseph W. Corning

49th New York, Lt. Colonel William C. Alberger

77th New York, Captain Nathan S. Babcock

2nd Division Artillery, Captain Romeyn M. Ayres

Battery B, Maryland Light Artillery, Lt. Theodore J. Vanneman

1st Independent Battery, New York Light Artillery, Captain Andrew Cowan

Battery F, 5th United States Artillery, Lt. Leonard Martin