The 6th New York Militia helped out as a 90-day regiment during the first summer of the war. Zook served as the military governor in
Annapolis, seeking support from politically influential men there to achieve a regimental command of his own. After he was mustered out, he raised the
57th New York Infantry (National Guard Rifles) and became its
colonel on October 19, 1861. Zook's first combat was during the
Seven Days Battles of 1862. His regiment was assigned to
William H. French's brigade in
Edwin V. Sumner's division of the
Army of the Potomac, under
Maj. Gen. George B. McClellan. Zook was personally scouting far out in front of his regiment in the run-up to the
Battle of Gaines' Mill, got behind enemy lines, and found that
Confederate Maj. Gen.
John B. Magruder was conducting an elaborate deception, making it appear that he had significantly more troops in his sector than he actually had. Zook's discovery was reported up to McClellan, but it was ignored, and
Union troops that could have been used successfully elsewhere remained tied down.
Fredericksburg Zook was forced to go on medical leave, probably due to chronic and disabling
rheumatism, thus missing the
Battle of Antietam. When he returned to the Army he was given command of French's brigade (3rd Brigade, 1st Division,
II Corps) under division commander Maj. Gen.
Winfield S. Hancock. The brigade was one of the first to arrive at
Fredericksburg, Virginia, and he wanted to cross over the
Rappahannock River as quickly as possible, before Confederate General
Robert E. Lee could reinforce the town and the heights beyond it. However, Army of the Potomac commander Maj. Gen.
Ambrose Burnside prevented the movement, wanting to wait for his army to concentrate and to receive pontoon bridges to make the river crossing. Zook wrote on December 10, "If we had had the pontoons promised when we arrived here we could have the hills on the other side of the river without cost over 50 men—now it will cost at least 10,000 if not more." General Hancock praised Zook's attack for its "spirit". Zook wrote afterward, "Now by God, if I don't get my star, I'm coming home." After the battle, Zook briefly assumed command of the division while Hancock was absent on leave. Despite his successful promotion, however, the Battle of Fredericksburg affected him deeply: At the
Battle of Chancellorsville in May 1863, Zook's brigade fought in the defensive line around the Chancellor Mansion, but facing east, where combat was lighter and his men suffered only 188 casualties. Disabled again by rheumatism, he left on medical leave to
Washington, D.C., and rejoined his brigade at the end of June to march into Pennsylvania for the
Gettysburg campaign.
Gettysburg On July 2, 1863, the
second day of the
Battle of Gettysburg, Brig. Gen.
John C. Caldwell's division, including Zook's brigade, was sent to reinforce the crumbling
III Corps line that was being assaulted by the Confederate corps of Lt. Gen.
James Longstreet. Zook was directed by one of the III Corps staff officers toward the
Wheatfield to reinforce the brigade of Col.
Régis de Trobriand and to fill a gap near the Stony Hill. Zook, on horseback, led his men up the hill, which attracted the attention of men from the advancing 3rd and 7th South Carolina Infantry regiments, of
Joseph B. Kershaw's brigade. He was struck by rifle fire in the shoulder, chest, and abdomen, and taken behind the lines for medical treatment at a toll house on the Baltimore Pike. He died from his wounds on July 3 and is buried near the grave of
General Winfield Scott Hancock in
Montgomery Cemetery in
West Norriton Township, Pennsylvania, near
Norristown, Pennsylvania. He received a
brevet promotion to major general for Gettysburg, awarded as of July 2. A small monument near the Wheatfield Road commemorates Zook's death. One of his soldiers in the 57th New York later characterized Zook as "a good disciplinarian; he hated cowardice and shams; had no patience with a man that neglected duty; was blunt, somewhat severe, yet good hearted ... a born soldier, quick of intellect, and absolutely without fear." ==See also==