The following is taken from New York in the War of the Rebellion, 15th ed. Frederick Phisterer. Albany: J. B. Lyon Company, 1912.

This battery was organized about December 21, 1861, by the consolidation of Companies A and C, 2d Battalion, N. Y. Volunteer Artillery, with Henry J. McMahon as Captain. It was then known as Company B of that battalion. The companies composing it were recruited and organized at New York city, and there mustered in the service of the United States for three years December 9, 1861; they left the State December 16, 1861. In October, 1862, the company received the above designation, the battalion having been discontinued. December 12, 1863, one officer and eighteen enlisted men of the 4th Battery were transferred to it. At the expiration of its term of service, the men entitled thereto were discharged and the battery continued in service. It served at and near Washington, D. C., from December, 1861; in Williams' Division, 5th Corps, Army of the Potomac, from March, 1862; in Doubleday's Brigade, Department Rappahannock, from May, 1862; in the Reserve Artillery, Army of Virginia, from June, 1862; at the Relay House, Md., 8th Corps, from September, 1862; in the Artillery Reserve, Army of the Potomac, from January, 1863; in the 2d, and then 1st, Volunteer Brigade, Artillery Reserve, Army of the Potomac, from May, 1863; in the 4th Brigade, Artillery Reserve, Army of the Potomac, from August, 1863; in the 3d Volunteer Brigade, Artillery Reserve, Army of the Potomac, from September, 1863; in the 2d Brigade, Artillery Reserve, Army of the Potomac, from January, 1864; in the 3d Brigade of the same, from March, 1864; in the Artillery Brigade, 5th Corps, from May 16, 1864; in the 22d Corps from November, 1864; in the Department of West Virginia from December, 1864, and February 4, 1865, commanded by Capt. Patrick Hart, it was transferred to the 32d N. Y. Volunteer Battery, having, during its service, lost by death, killed in action, 8 enlisted men; of wounds received in action, 1 enlisted men; of disease and other causes, 3 enlisted men; total, 12.

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.

Fifteenth Independent Battery.—Capts., Henry J. McMahon, Patrick Hart. One officer and 18 men were transferred to this battery from the 4th in Dec. 1863. On the expiration of its term of service the original members (except veterans) were mustered out, and the veterans and recruits consolidated with the 32nd battery on Feb. 4. 1865. The 15th took part in the engagements at Chancellorsville, Gettysburg, Rappahannock Station, the Mine Run campaign, Wilderness, Spottsylvania, the North Anna, Totopotomy, Cold Harbor, first assault on Petersburg and the Weldon railroad. It was before Petersburg from June to Nov., 1864, when it was withdrawn from the front and returned to Washington, serving in the 22nd corps and the Department of West Virginia during the winter of 1864-65. It lost during service 9 men killed in action and 3 men from disease and other causes.