William F. Fox, Lt. Col. U. S. V., Regimental Losses in the American Civil War, 1861-1865: A Treatise on the extent and nature of the mortuary losses in the Union regiments, with full and exhaustive statistics compiled from the official records on file in the state military bureaus and at Washington

The largest number of officers killed in any infantry regiment in the Union Armies is found in the Sixty-first Pennsylvania, of the Sixth Corps, in which 19 officers were killed or mortally wounded during the war. Among the number were three colonels: Col. Rippey was killed at Fair Oaks; Col. Spear fell while leading a successful assault on Marye's Heights; and Col. Crosby, who had lost an arm at Fort Stevens, was killed in the final and victorious assault on Petersburg. The total loss of the Sixty-first in killed and died of wounds, was 19 officers and 218 enlisted men; total, 237. It was a gallant regiment and was bravely led, as its loss in officers clearly shows.

The following list embraces every regiment which lost 16 or more officers killed during the war:

A heavy artillery regiment had just twice as many line officers as an infantry regiment.

The largest regimental loss of officers killed in any one battle, occurred in the Seventh New Hampshire at the assault on Fort Wagner, the regiment losing 11 officers killed or mortally wounded in that bloody affair. Among the killed was Col. Putnam, who fell after he had gained an entrance within the outer works of the fort. He was a graduate of West Point and an officer of the Regular Army; like many other Regular officers he had received permission to accept the command of a volunteer regiment.

The Twenty-second New York Infantry lost at Manassas 19 officers killed and wounded out of 24 present in action; 9 of them were killed, among whom was the Lieutenant-Colonel, Gorton T. Thomas.

The following list includes every infantry regiment in the service which lost 8 or more officers killed in any one engagement: