What happened to the 2nd Brigade, 1st Division, Twelfth Corps at Antietam?

Alpheus Williams

Occasionally we are asked why Alpheus William’s division at Antietam did not have a Second Brigade. A look at the order of battle indeed shows that there was a First Brigade commanded by Samuel Crawford, and a Third Brigade commanded by George Gordon. While the four Ninth Corps divisions at Antietam were also two brigade organizations, the normal divisional organization in the Army of the Potomac was a three-brigade structure. Is there a typo on the order of battle?  Is the Third Brigade actually the second brigade of the division?  If not, is the Second Brigade detached and serving elsewhere.

When George McClellan began his organization of the Army of the Potomac in August 1861, Major General Nathanial Banks commanded one of the divisions in that nascent army.  This division is the direct ancestor Alpheus Williams division, the organization that pushed down the Smoketown Road 13 months later.  In the beginning, Banks’ division had four brigades:  

First Brigade commanded by Alpheus Williams

Second Brigade commanded by John J. Abercrombie (USMA 1822)

Third Brigade commanded by George Gordon (USMA 1846)

Geary’s Separate Brigade commanded by John Geary

Nathaniel Banks

Bank’s division was stationed in Western Maryland. It was destined to play a major role the campaigns in the Shenandoah Valley through the summer of 1862. In March of 1862 when President Lincoln imposed a corps level organization on McClellan’s army, Banks was elevated to command of the Fifth Corps.[i] When he moved up to corps command, Alpheus Williams assumed command of his division.  Dudley Donnelly, commander of the 28^th New York Infantry replaced Williams in command of the First Brigade.  James Shields commanded the second division of Bank’s corps.

The original Fifth Corps would last but three weeks.  On April 4, 1862 it was discontinued and resurrected as the Department of the Shenandoah remaining under the command of Banks.  Williams and Shields continued to command the department’s two divisions. 

George Hartsuff

This is where it gets a bit complicated.  On April 10, 1862 George Hartsuff (USMA 1852) replaced James Abercrombie in command of the Second Brigade.  The brigade was transferred to the Department of the Rappahannock on May 10^th.  On May 25^th, John Geary’s brigade (less Geary) was transferred to the Washington defenses.  A new brigade was created for him on June 6, 1862 consisting of the 5^th, 7^th, 29^th and 66^th Ohio Infantry Regiments.  For five weeks, this brigade continued in Alpheus Williams’ division as the Second Brigade.  During this period (May 27^th), Donnelly turned over command of the First Brigade of William’s division to Samuel Crawford. 

But it’s not over.  On July 16^th, Geary’s Brigade was transferred to Christopher Auger’s (formerly Shields’) division.  For a second time, William’s division was without a second brigade.  It would remain this way through the Maryland Campaign. 

Two brigades could therefore lay claim to being Alpheus Williams “lost” second brigade.  Both fought at Antietam.  The first one as we have seen, is the brigade of George Hartsuff.  It was a charter member of Nathaniel Banks division lead first by James Abercrombie and eventually commanded by Hartsuff.  At Antietam, it belonged to James Rickett’s division and fought in the Cornfield.

Hector Tyndale

The second is Geary’s “new” brigade.  It was only part of Williams’ division for five weeks until reassigned to Augur’s division.  Both Augur and Geary were wounded at Cedar Mountain on August 9, 1862.  This paved the way for George Greene to assume temporary divisional command and George Candy to replace the wounded Geary.  Candy was not in command of this brigade however at the battle of Antietam. For the two-day period of September 17 – 18 1862 Hector Tyndale commanded this unit.  The brigade advanced with other elements of George Greene division to the Dunker Church plateau.

After Antietam, William’s division would receive a new “second” brigade of green soldiers.  At Fredericksburg, this brigade was commanded by Thomas L. Kane and consisted of the 20^th Connecticut, 123^rd New York, and the 124^th and 125^th Pennsylvania.

While Alpheus Williams division only consisted of two brigades at Antietam, brigades previously associated with his command were not far away on the bloody northern flank of the battlefield. 

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[i] This corps should not be confused with the provisional Fifth Corps that McClellan later created on the Peninsula.