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, located in New York city, was ordered, April 19, 1861, to proceed to Washington, D. C., and left the State, commanded by Col. Joseph C. Pinckney, April 21, 1861. It was mustered in the United States service for three months at Annapolis, Md., and July 31, 1861, it was mustered out of the same at New York city.
In November, 1861, quite a large portion of the regiment entered the volunteer service as the nucleus of the 66th Volunteers, organized by Colonel Pinckney.
June 18, 1863, the regiment, then commanded by Col. Joel W. Mason, was ordered to Harrisburg, Pa., to serve thirty days; it left the State June 22, 1863, and was placed on duty at Baltimore, Md., serving in the 2d and 3d Separate Brigades, Middle Dept, 8th Corps; it was mustered out of the service of the United States at New York city, July 22, 1863.
The regiment, not in existence at this date, lost by death, of disease, in its service in 1863, one enlisted man.

The following is taken from Third Annual Report of the Bureau of Military Statistics of the State of New York, Albany: [The Bureau], (C. Wendell), 1866.
SIXTH REGIMENT N. Y. S. M.
The Sixth regiment, in the Second brigade, First division, of the militia organization, left New York on the 21st of April. The following were the field officers:
Colonel—Jos. C. Pinckney. 
Lieutenant-Colonel— Samuel K. Zook.
Major— Milton G. Rathbun. The Union Defense 'Committee contributed $4,000 towards purchasing of blankets, clothing, subsistence, &c., for the regiment, and the officers and their friends also assisted in finishing its equipment. The State also contributed to this, and subsequent to its de-parture furnished the members with a new uniform. The regiment was to have proceeded by rail to Washington but in consequence of the attack in the streets of Baltimore upon the Eighth Massachusetts, and the apprehension that obstructions might be placed upon the railroads to prevent the further transportation of troops, it was determined that the Sixth should go by water. The steamer Columbia was, accordingly chartered and provisioned by the Union Defense Committee, and sailed at 9 o'clock in the evening, in company with the steamers Baltic and Cuyler, the former having on board the Twelfth and the latter the Seventy-first New York Militia, the whole under command of Lieutenant-Col. Keyes, U. S. A. The fleet sailed for Fortress Monroe, where they were joined by another steamer with the First Rhode Island, and then proceeded under convoy of the United States Revenue steamer Harriet Lane up the Chesapeake Bay to Annapolis, where they arrived on the night of the 23d of April. On the 25th the regiment disembarked by order of General Butler, then in command at that point, and was directed to remain there until further orders should be received. On the same day a detachment of 100 men from the Sixth was ordered to seize and occupy Fort Madison, a water battery commanding the harbor; also to occupy an elevated spot on the right bank of the Severn, overlooking the city of Annapolis. Under direction of Colonel Pinckney, this was effected without opposition on the same night; fifty-men occupying Fort Madison, and the remainder, with two howitzers, holding the height on the river.
About the 1st of May a detachment of 250 men was sent up the. Severn to relieve the Eighth N. Y. S. M., then occupying a commanding position on the road to Baltimore. An earthwork was here thrown up and named " Fort Morgan," in honor of the Governor of New York. About the 12th of June the Thirteenth, N. Y, S. M., then at Annapolis, was ordered to Baltimore, and the different detachments of the Sixth were recalled from the positions they were then occupying; those at Fort Morgan being transferred to Annapolis Junction, to relieve the Twentieth N. Y. S. M., and the balance, of the regiment to the Naval Academy at Annapolis, Colonel Pinckney having become commandant of the post.
While at Annapolis an expedition was organized by the Sixth for the purpose of carrying assistance to Governor Hicks, whose life it was rumored was in danger from secessionists. One hundred infantry and a company of artillery, with two howitzers, under command of Colonel Pinckney, proceeded in a propeller to Cambridge, the residence of the Governor. Upon the approach of the boat, many of the secessionists fled from the town, but the Governor was found unharmed.
Upon receipt of the news of the battle of Bull Run, the regiment unanimously requested to he sent to the front. The request was not granted, and on the 29th of July the regiment was relieved from duty by the First Pennsylvania Reserves, and then proceeded to New York, where it was mustered out of service. Col. Pinckney took immediate steps to organize a volunteer regiment for three years service. In this he was joined by many of the officers and men of the Sixth, and their efforts resulted in raising in the short space of sixty days, a full regiment, known as the sixty-sixth New York Volunteers. Lieutenant-Colonel Zook raised the Fifty-seventh New York Volunteers.