The following is taken from New York in the War of the Rebellion, 3rd ed. Frederick Phisterer. Albany: J. B. Lyon Company, 1912.

July 26, 1861, Col. Othneil De Forrest received authority from the War Department to recruit a brigade of cavalry for a service of three years. He recruited this regiment, as the Ira Harris Cavalry; after the organization had been turned over to the State, it was, October 16, 1861, designated the First Ira Harris Guard, and after its completion, November 14, 1861, the 5th Regiment of Cavalry. The Bliss Cavalry, an incomplete organization, recruited by Col. W. S. Bliss, was merged into the regiment, which was organized at Camp Scott, Staten Island, where its companies were mustered in the service of the United States: A on August 15, 1861; B on August 21, C on September 3, D on October 1, E on the 7th, and F on the 21st of September, G on the 9th, H on the 28th, and I, K, L and M, on the 31st of October, 1861. At the expiration of its term of service those entitled thereto were discharged and the regiment continued in the service.

The companies were recruited principally: A, B, K — Bliss Cavalry, M — Bliss Cavalry — at New York city; C at New York city, Troy and Kingston; D at Springfield, Mass., and New York city; E at Allegany, Kennedy, Richburgh, Belmont, East Rushford, Friendship, Ellicottsville, Cuba, Black Creek, Little Valley, Scio, Genesee, Farmersville, Great Valley and Wellsville; F at East Pike, East Gainesville, Castile, Attica, Oramel, Wellsville, China, Hume, Sardinia and Freedom; G, intended originally for a so-called Harlan's Cavalry, at Pike, Oswego and Elmira; H at Crown Point; I—Bliss Cavalry—.at Princeton, Passaic and Plainfield, N. J., and Brooklyn and Newburgh; and L at Hudson, Athens and Catskill.

The regiment left the State November 18, 1861, and served in the Department of Annapolis, Md., from November, 1861; in the 5th Corps and Department of the Shenandoah, from March, 1862; in the 2d Corps, Army of Virginia, from June, 1862; in Stahel's Division, defenses of Washington, from September, 1862; in the 3d Brigade, 3d Division, 22d Corps, Department Washington, from March, 1863; in the 1st Brigade, 3d Division, Cavalry, Army of the Potomac, from June 28, 1863; in the 2d Brigade, 3d Division, Cavalry, Army of the Potomac, from August, 1863; in the 1st Brigade, 3d Division, Cavalry, Army of the Potomac, from September, 1863; with the Army of the Potomac, detached in the 9th Corps, part of May, 1864; with the Cavalry Corps again from about end of May, 1864; in the Army of the Shenandoah, from October, 1864, and in the Department of West Virginia, from March, 1865, until July 19, 1865, when, commanded by Col. Amos H. White, it was mustered out and honorably discharged at Winchester, Va.

During its service, the regiment lost by death killed in action, 4 officers, 62 enlisted men; died of wounds received in action, 4 officers, 20 enlisted men; died of disease and other causes, 5 officers, 222 enlisted men; total, 13 officers, 307 enlisted men; aggregate, 320, of whom 104 enlisted men died in the hands of the enemy.

The following is taken from The Union army: a history of military affairs in the loyal states, 1861-65 -- records of the regiments in the Union army -- cyclopedia of battles -- memoirs of commanders and soldiers, Volume II: New York, Maryland, West Virginia and Ohio. Madison, WI: Federal Pub. Co., 1908.

Fifth Cavalry.—Cols., Othneil De Forest, John Hammond, Amos H. White; Lieut. -Cols., Robert Johnstone, John Hammond, William P. Bacon. Amos H. White, Theodore A. Boice; Majs., Philip G. Vaught, Washington Wheeler, John Hammond, Abram H. Krom, Elmer J. Barker, James Davidson, William P. Pratt, Amos H. White, Theodore A. Boice, George H. Gardner, William P. Bacon, James A. Penfield, Tiberly C. Abbott, Henry A. D. Merritt. Authority to recruit this regiment was received by Col. De Forest from the war department on July 26, 1861. The regiment, originally known as the "Ira Harris cavalry," rendezvoused at Camp Scott, Staten island, where it was mustered into the U. S. service from Aug. 15 to Oct 31, 1861. The companies of which it was composed were principally recruited in the counties of New York, Kings, Allegany, Cattaraugus, Wyoming, Tioga, Essex and Greene. A part of Co. D came from Springfield, Mass., and part of Co. I from Princeton, Passaic and Plainfield, N. J. The original members were mustered out by detachments in 1864 and the regiment, composed of veterans and recruits, continued in service until July 19, 1865, when it was mustered out and honorably discharged at Winchester, Va. The regiment left the state, nearly 1,200 strong, Nov. 18, 1861, and was stationed at Annapolis until the spring of 1862. That year it served in the 5th corps, Department of the Shenandoah; in the 2nd corps. Army of Virginia; and in Stahel's division in the defenses of Washington. It started on its first campaign down the Shenandoah Valley in April, 1862, and at Front Royal, Strasburg and Middletown, sustained a loss of 75 killed, wounded and missing. As Gen. Banks fell back before Gen. Jackson, the regiment was cut off at Strasburg, but saved Banks' wagon train and Hampton's battery, and escorted them in safety by a circuitous route through the mountains into Maryland. It lost 24 men at Barnett's ford, and 23 in an action near Orange Court House. In the latter engagement it distinguished itself by driving the 7th Va. cavalry and capturing 47 prisoners, incluring the commanding officer. Maj. Marshall. It took an active part in Gen. Pope's campaign, being selected as body-guard to that general. In 1863 the regiment served in the 3d brigade, 3d division, 22nd corps at Washington; in the ist and 2nd brigades, 3d cavalry division. Army of the Potomac; and was repeatedly in action during the year, its heaviest losses being sustained at Little River turnpike, loss 42; at Hanover, Pa., loss 54; at Hagerstown, loss 91; at Brandy Station, loss 25; and in a second action there, loss 28; at Buckland mills, loss 22. It then served with the cavalry corps. Army of the Potomac, until Oct., 1864; in the Army of the Shenandoah until the opening of the final campaign in 1865; and in the Department of West Virginia from March. 1865. It participated in Kilpatrick's raid to Richmond in the spring of 1864, sustaining considerable loss, Maj. Merritt, being among the captured. It was heavily engaged at the battle of the Wilderness, where it opened the fight at Parker's store, and met with a loss of 63 killed, wounded and missing. Its losses at Spottsylvania Court House were 16; at North Anna 25; at Cold Harbor 43; in the raid to the South Side and Danville railroads in June 98; at Smithfield 19; and at the Opequan 17. The regiment returned home under command of Col. White, with only about 550 men out of a total enrollment of nearly 2,500. It had participated in nearly 175 battles and skirmishes and established a well-earned reputation for gallantry and high soldierly conduct. Its total losses by death were 5 officers and 62 men killed in action; 2 officers and 24 men died of wounds received in action; 4 officers and 222 men died of disease, accident and other causes; a total of 11 officers and 308 men, of whom 99 died in Confederate prisons, a larger loss from this source than was sustained by any other cavalry regiment from the state. Medals of honor were conferred upon three of the regiment by the secretary of war for distinguished gallantry in action, viz.: Sergt. Thomas Burke, for capture of a battleflag at Hanover, Pa.; Sergt. David S. Scofield, for the capture of a flag at Cedar creek, Va. ; and on Corp. John Walsh, for the capture of a flag at the same engagement.