Reports of Brig. Gen. Tyler, Connecticut Militia, commanding First Division HDQRS. First Division Dep’t Northeastern Virginia, Washington City, July 27, 1861
349     “Through one of my staff, Lieutenant O’Rorke, of the Engineers, I was promptly notified as to my change in the progress of their columns…”
351     “From my own personal staff I received in every instance prompt and gallant assistance, and my thanks are due to Captain’s Baird and Merrill, Lieutenants Houston, Abbott, Upton, O’Rorke, and Audenried for gallant conduct and the prompt and valuable assistance they rendered me. Lieutenants Abbott and Upton were both wounded and each had a horse killed under him, as also had Lieutenant O’Rorke.”

Port Royal Expeditionary Forces: Staff of Gen. Thomas W. Sherman
Reconnaissances of James, Bird, and Tybee Islands

Report of Lieut. P. H. O’Rorke, U. S. Corps. of Engineers, of condition of the works of investment on February 28, 1862, Daufuskie Island, S. C., February 28, 1862
143-144           “SIR: In compliance with your directions, I have the honor to submit the following report, showing the amount of work accomplished and the present condition of the batteries on Jones and Bird Islands:
About the 7^th of this month it was determined by you to wait no longer the long delayed entrance of the naval force into the Savannah River. It was at the same time directed that a battery should be planted, under cover of the night, at Venus Point, on Jones Island, at the earliest practicable moment. The next day the proposed battery was staked out, and on the same evening an attempt was made to transport the guns and material to the landing on Mud River. This movement, after the greatest exertions to carry it into execution, had to be abandoned for that night, in consequence of the severe storm which came up and the extreme darkness of the night. The attempt was made again on the ensuing night, and was most successful. Five Parrott guns and an 8 inch siege howitzer were landed on Jones Island, and two of the guns were moved about 200 yards towards their intended positions. Four platforms were laid the same night, two others commenced, and a magazine built. As it was not deemed expedient to show ourselves in the daytime, the work was suspended until the next night. The following morning saw our guns in position and ready for action.
Fatigue parties were now set at work to throw up a parapet as rapidly as possible, and by night a parapet 8 feet wide and about 3 feet high was thrown up in front of the guns. At the same time a thin covering of earth was thrown around the magazine, in addition to sand bags which had been placed around it at first. In consequence of the softness of the mud of which the island is made, it was found impossible to make the parapet sufficiently high at once or to give it a regular shape. The first occasion for using the guns showed that the platforms furnished by the Ordnance Department were too narrow to allow them to be traveled sufficiently. Immediate steps were taken to provide the lumber necessary to enlarge the platforms. A grillage was formed of logs, and upon these planks were laid, increasing the width to 20 feet. Some of the lumber used had to be transported from the Winfield Scott, and other pieces obtained by pulling down houses on Daufuskie Island.
The subsequent engagement with the gunboats of the enemy showed that our platforms were now sufficiently wide and firm. The spring tides now coming on, the whole island was covered with water, and our efforts were immediately directed to the completion of a level around the work. After having the battery twice flooded this was accomplished. The work for some days could now be prosecuted only at low water, and then with great difficulty, in consequence of the softening of the surface. Since then the work has been progressing constantly though slowly.
There is now a parapet around the work over 1,000 feet in length, from 6 to 10 feet thick, differing on different faces, and from 3 to 4 feet high. The magazine is covered on top by 5 feet of earth and sandbags, and on the sides by about 10 feet in thickness of the same material. It is not entirely completed. A board walk has been built about 6 feet in rear of the platforms, to extend the whole length of the work, with other walks leading from this to the platforms. A good wheelbarrow road has been made across the island by laying poles about 2 feet apart and placing boards upon them. Some of the lumber last brought from Hilton Head has been applied towards making the garrison as comfortable as possible.
About the 19^th of this month it was decided by you that a battery should be placed on the north end of Bird Island. It was staked out the next day, and the same night the guns and material were taken from Daufuskie Island to that point and landed. On the following day the platforms were laid and the guns put in position. Since then the levee has been built around the work, and in addition to this another has been built for the protection of the camp of the infantry supports against high tides. A magazine has also been built here, and secured as far as practicable. A strong wind prevented our flats from being towed backward and forward for two or three days, and consequently has prevented us from supplying the battery with sufficient lumber to this time. Some of the platforms have begun to sink, and will have to be relaid. Profiles have been put up on this battery, and it is steadily progressing. Timbers for the foundation of the platform for the columbiad have been got out of the houses pulled down on this island, and are ready as soon as transportation can be had for them.

Report of Brig. Gen. Gouverneur K. Warren, U. S. Army, commanding Third Brigade, Headquarters Third Brigade, December 17, 1862
429      “The whole presented to the view of the enemy the next morning a complete line, and could have been connected and strengthened during the day without interference from him. I designed to assign this duty to Colonel O’Rorke, with his regiment, the One hundred and fortieth New York Volunteers, and they were kept in reserve for this purpose during the night.”

Chancellorsville (May 1-3, 1863)
Briefly Third Brigade Commander after Brig. Gen. Gouverneur K. Warren was wounded.

Report of Col. Patrick H. O’Rorke, One hundred and fortieth New York Infantry, commanding Third Brigade, Camp near Potomac Creek, VA., May 7, 1863.
541-543           “SIR: In compliance with special orders of this date from division headquarters, I have the honor to submit the following report of the operations of the Third Brigade during the recent movements of this army: On the morning of April 27, the brigade broke camp and moved with the division, encamping for the night at Hartwood Church. On the 28th, we marched to Crittenden’s Mills, where we passed the night. On the 29th, we moved at 7 a. m. at the head of the division: crossed the Rappahannock at Kelly’s Ford; thence marched to Ely’s Ford, on the Rapidan; crossed it after dark, and encamped. The next morning (April 30), we marched to the United States Ford, and thence to Chancellorsville, half a mile beyond which we encamped and threw out pickets to cover our front. On May 1, we moved with the division, the First and Second Brigades being in advance of us. When the head of the column met the enemy advancing from Fredericksburg, the Third Brigade was deployed in line of battle, extending across the road, and advanced to the support of the troops in our front until halted by General Sykes. Here we remained until 2 p. m. It having been discovered that the enemy was turning our right flank, six companies of the One hundred and forty-sixth New York Volunteers were sent out as skirmishers to protect that flank. The Fifth New York Volunteers also deployed skirmishers through the woods on the left of the division. Some of these skirmishers were captured by the enemy. Their names are given in the list of casualties. When ordered to retire, the brigade fell back in line of battle, in good order, until behind the Second Corps, when it was formed in column in mass. After resting here half an hour, we were ordered to return to the ground we had left in the morning, which we did. The Second Corps then returned to Chancellorsville, leaving this brigade next the enemy. As the last division of the Second Corps passed us, General Hancock, who commanded it, sent word to me, by Dr. Winslow, that the enemy was following him in force, and that I had better get my command into the road and retire after his division. Although the suggestion, coming from such a source, was entitled to some consideration, yet, as I had no orders from General Sykes to leave the ground, I concluded to hold it, if possible, until I should receive such orders. I immediately deployed the brigade into line of battle, the left resting on a creek which crossed the road and the right connecting with the Second Brigade. This movement was not finished before our pickets were driven in, and the enemy was seen advancing over the crest of the ridge on the opposite side of the ravine, in our front. They showed two lines, each about equal to a regimental front. The right of their line I could not see, as it was covered by a grove of young pines. As the One hundred and fortieth and One hundred and forty-sixth New York Volunteers were under fire for the first time, I thought it prudent to commence firing before the enemy got very close. As soon as the second line of the enemy showed itself, I gave the command to commence firing. The enemy had been firing quite rapidly for some time before a gun was fired from my brigade. At the command, a rapid fire by file was commenced, and continued until the enemy disappeared over the crest of the hill in our front, when we ceased. We were not again attacked. Three of the enemy were captured by the One hundred and fortieth New York Volunteers. At dark, the pioneers of the brigade were set to work felling trees in our front and digging a rifle-pit across the road on our left flank. At 2 o’clock on the morning of the 2d, the brigade moved from its position back through Chancellorsville, and took a position in front of the road leading toward Banks Ford. The pickets were left out until daylight, and then withdrawn at once. This duty was performed by Lieutenant-Colonel Jenkins, One hundred and forty-sixth New York Volunteers, who took command of all the pickets of the division and brought them in safely. We remained in this position until evening, having details at work all day felling trees to form an abatis, and digging a rifle-pit. When the attack was made on the Eleventh Corps, we were ordered out, and marched at double-quick time toward the point where the action was going on. We were first posted near some old rifle-pits of the enemy, beyond the road to Ely’s Ford, connecting on the right with the First Brigade, and our left supporting a battery. At 2 a. in. of May 3, we were again moved to the right, and posted in rear of the Second Brigade, which was in line of battle. In the afternoon of the 5th, we were again moved farther to the right, to support General Ayres brigade. At 2 o’clock on the morning of the 6th, we prepared to recross the Rappahannock. Upon reaching the United States Ford, the brigade was placed in reserve in the rear of the First and Second, which were put in position to cover the crossing. We crossed with the division, and arrived at our present camp in the evening. I send herewith a complete list of casualties in the several regiments of the brigade. Before ending this report, I would respectfully call your attention to the praiseworthy conduct of the two new regiments of the brigade. The officers and men of the Fifth New York Volunteers behaved as they have always done; I can give them no higher praise. The officers and men of the One hundred and fortieth and One hundred and forty-sixth New York Volunteers vied with them in their cool- ness, attention to duty, and ready compliance with orders. I was ably seconded in all my efforts, both on the march and in the field, by the staff officers of the brigade, consisting of Captain Marvin, assistant adjutant-general, Captain [Edgar W.J Warren, commissary, and Lieutenant [Thomas E.] Fish, acting assistant adjunct-general, who acted as aides in the field and performed their duties creditably. Very respectfully, your obedient servant, P. H. RORKE, Colonel 140th New York Volunteers, Commanding Brigade.”

Reports of Brig. Gen. Romeyn B. Ayres, U. S. Army, commanding Second Division, HDQRS. Second Division, Fifth Army Corps, July 28^th, 1863
635      “The brigade commanders Col. H. Day, First Brigade, Col. S. Burbank, Second Brigade, and, after the fall of General Weed and Colonel O’Rorke, Colonel Garrard, Third Brigade performed their duties with coolness and gallantry.”
            “Col. P. H. ORorke, One hundred and fortieth New York Volunteers and first lieutenant U. S. Engineers, was a brave and valuable officer.”
Report of Col. Gerrard, One hundred and forty-sixth New York Infantry, HDQRS. Third Brig., Second Div., Fifth Army Corps, Camp near Berlin, MD., July 16, 1863
651      “At this point the leading regiment, under the direction of General Warren, chief engineer Army of the Potomac, was led to the left, up on what is known as Round Top ridge. Hazlett’s battery ascended the ridge immediately in rear of this regiment (the One hundred and fortieth New York Volunteers, Col. P. H. O’Rorke commanding), and went into battery on the summit. The One hundred and fortieth was formed in line, and was immediately closely engaged with the enemy at short musket-range on the left slope of the ridge. A portion of the First Division, Fifth Army Corps, was engaged to the left of the ridge, and this regiment and Hazlett’s battery were brought up to assist the First Division in repelling a heavy assault of the enemy, with the evident design of gaining this ridge. Colonel O’Rorke was mortally wounded at the head of his regiment while leading it into action.”