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

This regiment, Col. William H. Christian, was accepted by the State May 17, 1861, for a service of two years; organized at Elmira, and there mustered in the service of the United States for three months May 21, 1861. At the request of the general government, the Governor of the State, August 2, 1861, ordered it in the service of the United States for the unexpired portion of its term of State service. In May, 1863, its three years' men were transferred to the 97th Infantry. The companies were recruited: A, B, C and E at Utica; D at Hamilton; F at Whites-town ; G and H — originally intended for the 13th Regiment — at Rochester; I at Orislo any; and K at Candor; the men came principally from the counties of Madison, Monroe, Oneida and Tioga; a few from the counties of Chenango, Herkimer and Seneca.
The regiment left the State June 19, 1861; served at and near Washington, D. C, from June 20, 1861; in McCunn's Brigade, from July 21, 1861; in Heintzelman's Brigade, Division of Potomac, from August 4, 1861; in Slocum's Brigade, Franklin's Division, Army of the Potomac, from October 15, 1861; in Wadsworth's command, at Fort Lyon, Va., from November, 1861; in 1st Brigade, 2d Division, Department of Rappahannock, from May, 1862; in 2d Brigade, 2d Division, 3d Corps, Army of Virginia, from June 26, 1862; in 2d Brigade, 2d Division, 1st Corps, Army of the Potomac, from September 12, 1862, and was honorably discharged and mustered out, under Col. Richard H. Richardson, May 28, 1863; Companies H and K, May 24th, at Utica.
During its service the regiment lost by death, killed in action, 3 officers, 62 enlisted men; of wounds received in action, 2 officers, 41 enlisted men; of disease and other causes, 42 enlisted men; total, 5 officers, 145 enlisted men; aggregate, 150; of whom 1 enlisted man 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. Madison, WI: Federal Pub. Co., 1908. volume II.

Twenty-sixth Infantry.—Cols., William H. Christian, Richard A. Richardson; Lieut.-Cols., Richard A. Richardson, Gilbert S. Jennings; Majs., Gilbert S. Jennings, Ezra F. Wetmore. The 26th, the 2nd Oneida regiment, was composed of six companies from Oneida county, two from Monroe, one from Tioga and one from Madison, and was mustered into the U. S. service May 21, 1861, at Elmira, for a three months' term. It left the state on June 19, for Washington; camped for a month on Meridian hill; then moved to Alexandria; was stationed in that vicinity at various points during the autumn, and established winter quarters at Fort Lyon, where it was attached to Wadsworth's brigade. When the advance of the army commenced in March, 1862, it was assigned to the 1st brigade, and division, Department of the Rappahannock for a month, and it then became a part of the 2nd brigade, 2nd division, 3d corps, Army of Virginia. Under special orders from the war department the regiment was remustered on Aug. 21, 1861, for the remainder of two years' service. The regiment was present at Cedar mountain and participated in the campaign in Virginia under Gen. Pope, losing in the second battle of Bull Run 169 in killed, wounded and missing. On Sept. 12, it was assigned to the 2nd brigade, 2nd division, 1st corps, Army of the Potomac, and was active at South mountain and Antietam. At the battle of Fredericksburg it met with its heaviest loss. Out of 300 members engaged 170 were killed, wounded or missing, of whom 51 were mortally wounded. After the battle winter quarters were established at Belle Plain and occupied, except during the "Mud March," until the Chancellorsville movement in the spring of 1863, during which the regiment performed advance picket duty. It was mustered out at Utica, May 28, 1863, having lost 108 members by death from wounds and 42 by death from other causes.