Patrick Henry Monaghan (November 19, 1843 – October 22, 1917) was a native of Ireland who fought for the federal government of the United States (Union Army) during the American Civil War as a member of Company F of the 48th Pennsylvania Infantry.

[1] He received America's highest award for valor, the U.S. Medal of Honor, for recapturing the regimental flag of the 7th New York Heavy Artillery on June 17, 1864 while fighting in the Siege of Petersburg, Virginia.

[6][7] On August 12, 1861, Patrick H. Monaghan became one of the early responders to U.S. President Abraham Lincoln's call for volunteers to defend Washington, D.C. following the mid-April 1861 fall of Fort Sumter to the Confederate States Army.

After enrolling for military service in the American Civil War, Monaghan officially mustered in as a private with Company F of the 48th Pennsylvania Infantry.

[9] Armed with Harper's Ferry muskets, Monaghan and his fellow 48th Pennsylvania Volunteers were trained in basic light infantry tactics before being shipped on September 24 to Baltimore, Maryland via the Northern Central Railroad, where they transferred to the steamship, Georgia.

Moved back to Fortress Monroe in early June, they were then ordered to Newport News, Virginia where, on August 2, they sailed for Aquia Creek, and were transported from there two days later by rail to Fredericksburg, where they supported Union Army operation for roughly a week before being assigned to the Northern Virginia Campaign, during which they fought in the Battle of Cedar Mountain (August 9), engaged in operations at Kelly's Ford, White Sulphur Springs, Warrenton, and Manassas Junctions, and fought against the Confederate forces led by Stonewall Jackson in the Second Battle of Bull Run (August 28–30).

According to historian Samuel P. Bates, Monaghan and his fellow 48th Pennsylvanians reached the battlefield at Bull Run at 1 p.m. on August 29 after “the action already having begun”, and were quickly positioned on the Union Army's far right:[10] At three it formed in line of battle, with the Second Maryland on the right, the Sixth New Hampshire on the left, and the Forty-eighth in rear of the latter, and moved a cleared field toward the dense wood occupied by the enemy.

The regiment lost seven killed, sixty-one wounded [including Patrick H. Monaghan], ten prisoners, and seventy-four missing, an aggregate of one hundred and fifty-two.Re-engaging with the enemy the next day (August 30), the 48th Pennsylvanians experienced more intense combat during the Battle of Chantilly (September 1), during which the 48th Pennsylvania was again positioned at the far right of the Union Army.

[17] In recalling the events later for author Theophilus F. Rodenbough, Monaghan said:[18] After crossing the James River on the 15th of June, we marched rapidly toward Petersburg, and on the evening of the 16th debouched from a dense strip of woods, deployed, and double-quicked across a field toward the enemy’s works.

While in this position the most profound silence was maintained, as we could hear the enemy talking, and every man was notified to secure his tin cup and trappings so as to make no noise and be ready for a charge.

Before daylight the order came, and we, with the 36th Massachusetts, dashed forward, under a heavy fire, leaped the enemy’s breastworks, capturing four pieces of artillery, six hundred prisoners, and about a thousand stand of arms.

In leaping the breastworks, a rebel fired, with his gun so close to the left side of my head that my hair was singed, my cheek slightly burned, and ear injured by the concussion so that I feel the effects of it yet.

I was so elated over getting those colors that I merely called to the prisoners to follow me, and not knowing whether they did or not, ran excitedly back to the line which was still firing over us, who were in the hollow, at the retreating rebels beyond the thicket.

John L. Williams, of our company, jumped up, embraced me, and the boys pulled us both down, as the enemy had opened a pretty lively fire from their second line by this time.

We unfurled the flag and found it belonged to the 7th New York Heavy Artillery.Involved with his regiment in the June and July preparations for the mine placement and explosion at Petersburg, but not the ensuing Battle of the Crater (July 30), Monaghan and his fellow 48th Pennsylvanians next fought with Confederates in the Battle of Poplar Springs Church (September 30–October 2), and were then reassigned to the occupation of Fort Sedgwick from early December 1864 through April 1, 1865.

The next day, they participated in the Union's assault on Fort Mahone, and began the occupation of Petersburg (April 3), continuing in operations related to this action until their regiment was honorably mustered out on July 17, 1865.

Initially stationed in Harrisburg in July of that year, they were then reassigned to Pittsburgh in August until they were relieved by another regiment of the Pennsylvania National Guard.

[30][31] A naturalized citizen of the United States by the time of the 1900 federal census, Monaghan continued to reside in Girardville with his wife and children: Mary; Joseph, who was studying law; Margaret; Vincent, who had become a druggist's clerk; and Helen.