Colonel Dennis O’Kane, officer in the Union Army during the American Civil War, dies on July 4, 1863 of wounds sustained the previous day when fighting with the 69th Pennsylvania Irish Brigade at the Battle of Gettysburg.
Born in Coleraine, County Londonderry, O’Kane is a tavern owner in Philadelphia, Pennsylvania and a member of the 2nd Pennsylvania Militia regiment prior to the Civil War. When the conflict starts, he helps recruit the 24th Pennsylvania Volunteer Infantry, a unit that has the 2nd Pennsylvania Militia as its nucleus. Commissioned Major, Field and Staff, on May 1, 1861, he is with his regiment as it serves first in Maryland and then Virginia before their enlistment expires in July 1861.
In August 1861 O’Kane joins with many of the men from the 24th Pennsylvania in re-enlisting to continue the war effort, and they form the basis of what becomes the 69th Pennsylvania Infantry Regiment. Commissioned Lieutenant Colonel, Field and Staff on August 19, 1861, his new regiment is composed largely of Irish immigrants like himself, and they emblazon the Irish harp on their flag. The unit eventually is joined with the 71st, 72nd and 106th Pennsylvania Infantry Regiments to form the famous Philadelphia Brigade.
O’ Kane serves as second-in-command through 1862, participating in the Peninsular Campaign of May and June, the Second Battle of Bull Run in August, and the September 1862 Battle of Antietam, where his brigade is caught in the West Woods area and takes heavy losses. In November 1862, the 69th Pennsylvania’s commander, Colonel Joshua T. Owen, is promoted to Brigadier General, US Volunteers. O’Kane is advanced to Colonel on December 1, 1862 to fill the vacancy.
At the Battle of Fredericksburg on December 14, 1862, O’Kane leads his men in the third of four waves of futile Union charges on strong Confederate positions at Marye’s Heights south of the town, and sees his regiment sustain fifty-one casualties. In May 1863 during the Battle of Chancellorsville, his brigade is held in reserve and sees limited action.
During the Battle of Gettysburg in July 1863, O’Kane finds the 69th Pennsylvania positioned along a rock fencing in the middle of the Union lines that becomes famous as “The Angle.” That position becomes the epicenter of Pickett’s Charge on July 3, the third day of the battle, as the remnants of the Confederate forces, having been much devastated from Union artillery fire, crash over the rock walls and engage the Philadelphia Brigade in brutal hand-to-hand fighting.
O’Kane is shot in the head at the wall and dies the following day. His regiment again takes high casualties but succeeds in helping to repulse the rebels and defeat the charge. The monument for the 69th Pennsylvania Infantry in Gettysburg National Military Park stands on the spot where O’Kane was mortally wounded.