Manassas National Battlefield Park

Samuel Peter Heintzelman

From the Peninsula to Maryland: Heintzelman's role in the summer of 1862

Photograph of Samuel Heintzelman
Samuel Heintzelman
Library of Congress

Quick Facts

Significance:
Major General commanding III Corps Union Army of the Potomac
Place of Birth:
Manheim, PA
Date of Birth
September 30, 1805
Place of Death:
Washington, DC
Date of Death
May 01, 1880
Place of Burial:
Buffalo, NY
Cemetery Name
Forest Lawn Cemetery

While Samuel Heintzelman's experience, devotion to duty, and bravery were undeniable, he lacked requisite attributes of high command, including initiative, imagination, and administrative ability. He was gifted at leading a squad or regiment in combat, but when asked to command a Union corps, he floundered.

It was in this latter capacity that he took part in the Peninsula and Northern Virginia Campaigns, commanding the III Corps of the Army of the Potomac.

It was Heintzelman who, leading the Union advance at Yorktown, vastly overestimated the strength of the Confederate defenders. This inflation of Confederate numbers was enough to convince the naturally cautious McClellan to pull back from the advance and lay siege to the village, affectively stalling the campaign. This natural caution and penchant for magnifying the difficulties before him only increased for Heintzelman during the Peninsula Campaign. His corps performed well, but the success was due to the fact that Heintzelman commanded two of the army's best combat divisions under Joseph Hooker and Philip Kearny. Both men led effectively and fought valiantly while Heintzelman exercised little influence and control.

The same can be said of the Northern Virginia Campaign, which proved to be Heintzelman's last as a corps commander as a result of his failure to exhibit the attributes of an officer destined for future responsibilities.

After pulling back from Richmond, Heintzelman's corps embarked from Fort Monroe and landed at Alexandria on August 22. His men, along with Porter's corps were immediately pushed forward to join Pope near Manassas. Philip Kearny's division of Heintzelman's corps reached Pope on the 24th and Joseph Hooker's division joined the Army of Virginia the following day. They were among the few divisions of the Army of the Potomac to actually participate in the Second Battle of Manassas (Bull Run).

During the Maryland Campaign the III Corps remained in Washington, D.C.

Though the Corps rejoined the Army of the Potomac following the campaign, Heintzelman did not accompany them. After being relieved of corps command on October 12 he was assigned to the Military District of Washington where he remained for nearly 2 years.