Born on February 15th,
1804, Civil War Union Brevet Brigadier General. After graduating
from the United States Military Academy in 1823 (with future
Union Generals Lorenzo Thomas and George S. Greene), he
was posted to the 2nd United States Infantry, a unit that
he would be associated with nearly his entire career.
His military service
in the long years before the Civil War exhibited the typical
stations of a career soldier, serving garrison posted on
the Great lakes, on the East Coast and in the Western Frontier.
He directed portions of his unit in the 1832 Black Hawk
War (where he saw no action) in the Florida Seminole wars
of 1839 and 1842, and during the Mexican War. He was promoted
to Captain in 1838, fifteen years after his graduation as
a 2nd Lieutenant. He was promoted to Major in 1852, and
from Sept. 4, 1859 through May 15, 1860, Major Day commanded
Ft. Laramie.
Day was promoted to
Lieutenant Colonel of the 2nd Infantry in February 1861.
Less than a year later he was promoted to full Colonel of
the 6th United States Infantry in January 1862. As
one of the oldest officers in the Army, he was typically
performed staff and recruitment posts. However, events of
June and July 1863 thrust him into his single combat command
of the war, and his first combat field command since the
Mexican War. When Army of the Potomac commander General
Joseph Hooker resigned as its head in late June 1863, Fifth
Corps commander Major General George G. Meade was detailed
to replace him., Major General George Sykes took over command
of the Fifth Corps. Sykes' First Division was then
taken over by Brigadier General Romeyn B. Ayers, and Colonel
Hannibal Day was assigned to lead Ayers old First Brigade,
made up of Regular Army troops.
Having led the brigade
for only three days, and being wholly unfamiliar with his
officers and men, Colonel Day was positioned on the Federal
Left flank on the Second day of the Battle of Gettysburg
(July 2, 1863). When General John S. Caldwell's Division
was thrown into the maelstrom of the Wheatfield, Colonel
Day's brigade was sent in support, ands ended up at the
eastern edge of the Rose Woods. His horse was killed in
the action there, and his men, while lying prone, were flanked
when Confederate forces pushed back the brigade in his right.
He led the Regulars in an orderly retreat, but sustained
382 casualties during his relatively brief time on the field.
After regrouping near Little Round Top, the brigade saw
no more action. Less than a month later (August 1)
Colonel Day retired on his own application after forty consecutive
years of service. He spent the next year on volunteer court
martial duty. On March 13, 1864 he received a brevet of
Brigadier general, US Regular Army for "long and faithful
services in the Army". The old soldier passed away
in Morristown, New Jersey on March 26, 1891.
