HDQRS. 126TH REGIMENT PENNSYLVANIA VOLUNTEERS,
Camp near Falmouth, Pa.[*], April 11, 1863.
Brig. Gen. A. A. HUMPHREYS,
Commanding Third Division, Fifth Army Corps.
GENERAL: In compliance with your request of yesterday evening, I have the honor to state that when the One hundred and twenty-sixth Regiment Pennsylvania Volunteers arrived at the battle-field of Antietam and occupied the position vacated by the troops of General Morell, about 11 a. m. of the 18th of September, the number of men present was 730. I form this estimate of the strength of the regiment at that time from my recollection of conversations with Colonel Elder, who then commanded the regiment.
I have the honor to be, very respectfully, your obedient servant,
D. WATSON ROWE,
Lieutenant-Colonel, Commanding 126th Pennsylvania Volunteers.
Source: OR1
*[it seems more likely that the Regiment was at Falmouth, Virginia in April 1863 - brd.]
1 US War Department, The War of the Rebellion: a Compilation of the Official Records of the Union and Confederate Armies (OR), 128 vols., Washington DC: US Government Printing Office, 1880-1901, Vol. 51/Part1 (Ser #107), pg. 161 [AotW citation 156]