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Federal Regiment

123rd Pennsylvania Infantry

Organized: Allegheny City, PA; mustered in 08/1862
Disbanded/Mustered out: Harrisburg, PA 05/13/1863


Commanding Officer on the Antietam Campaign:
  Col. John B. Clark


   Springfield Rifle-Musket


This Regiment's Chain of Command:
  Army - Army of the Potomac
  Corps - Fifth (V) Army Corps
  Division - 3rd Division, V Corps
  Brigade - 2nd Brigade, 3rd Division, V Corps

Unit history

A 6-month unit formed largely of Allegheny County men.

On the Antietam Campaign

"At the Capital, the regiment exchanged its arms, Austrian muskets, with which it had at first been supplied, for Springfield rifles. On the morning of the 14th of September, the command started on the march through Maryland, and arrived near Frederick at night-fall of the 16th. Here the division remained during the 17th, under orders to cover Frederick from the direction of Harper's Ferry. At sunset it received orders to move to Antietam, and at the moment of receiving the orders the sound of battle was heard for the first time that day. The command was again put upon the march, and for the entire night, up and down the rugged way it was urged forward and at a little after sunrise on the following morning, was halted on the Antietam battle-field, a short distance from Sharpsburg."1

Battlefield Tablets for this Unit

Tablet #19: Humphreys' Division, Fifth Army Corps - 14 Sep, 6 AM to 18 Sep, 7 AM
Tablet #33: Fifth Army Corps - 15 Sep, 2 PM to 16 Sep, 12 PM

After the Antietam Campaign

The Regiment continued in service with the Army of the Potomac seeing significant combat at Fredericksburg and Chancellorsville before mustering out.

More on the Web

See Bates' Regimental history of the 123rd transcribed online by Alice J. Gayley on PA-Roots.

We have 6 individuals who were on the Maryland Campaign in the AotW database for this unit:


Co. Rank Name Casualty? Details*
BPvtWhite, Leartes Died   10/19     We have some details for this person
EPvtSiemon, George FrederickMWIA   09/14     We have some details for this person
GPvtFairly, Samuel Died   11/14     We have some details for this person
IPvtThompson, William Died   11/11     We have some details for this person
KPvtCallahan, Peter MWIA   09/14     We have some details for this person
F&SColClark, John B        We have a picture for this person We have some details for this person


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1   Bates, Samuel Penniman, History of the Pennsylvania Volunteers, 1861-65, Harrisburg: State of Pennsylvania, 1868-1871  [AotW citation 115]