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

One hundred men of the 1st Cavalry, located in New York city, principally of Company A, commanded by Lieut. Col. Thomas C. Devin of the regiment as captain, volunteered, upon the request of the General Government for some cavalry, for a service of three months, and left the State, July 3, 1861. This company was mustered in the service of the United States at Washington, D. C., July 14, 1861, and mustered out and honorably discharged at New York city, October 23, 1861. The company and regiment are, at the present date, not in existence.

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.

First Cavalry.—Capt. Devin's company, '"Jackson Horse Guards." One hundred men of the ist cavalry, of New York city, under command of Lieut.-Col. Devin as captain, volunteered for three months' service, when the general government early in July, 1861, requested some mounted troops. It left the state on July 3, and was mustered into the U. S. service for three months at Washington, July 14, 1861. It was mustered out at New York city, Oct. 23, 1861.