Charles R. Leonard, a Private in New York 27th Infantry otherwise known as the "Union Regiment", Company C, which, according to History of the 27th Regiment N.Y. vols, was recruited in Binghamton, New York, by Capt. Jos. J. Bartlett in 1861.

See p. 561 of Binghamton: It's growth and development and the factors in its history, 1800-1900, by W.S. Lawyer, 1900. [Link]

Found on nps.gov as follows:

Soldier's Rank In: Private

Soldier's Rank Out: Private

Film Number: M551 ROLL 82

Organized at Elmira, N. Y., May 21, 1861. Mustered in June 15, 1861, and left State for Washington, D. C., July 10. Attached to Porter's Brigade, Hunter's Division, McDowell's Army of Northeast Virginia, to August, 1861. Heintzelman's Brigade, Division of the Potomac, to October, 1861. Slocum's Brigade, Franklin's Division, Army of the Potomac, to March, 1862. Slocum's 2nd Brigade, Franklin's 1st Division, 1st Army Corps, Army of the Potomac, to May, 1862. 2nd Brigade, 1st Division, 6th Army Corps, to May, 1863.

Service:

Advance on Manassas, Va., July 16-21, 1861. Battle of Bull Run, Va., July 21. Duty in the Defences of Washington, D. C., till March, 1862. Expedition to Pohick Church October 3, 1861. Advance on Manassas, Va., March 10-15, 1862. McDowell's advance on Fredricksburg April 4-12. Ordered to the Peninsula, Virginia, April 22. Siege of Yorktown, Va., April 24-May 4, on transports. West Point May 7-8. Near Mechanicsville May 20. Seven days before Richmond June 25-July 1. Gaines' Mill and Chickahominy June 27. White Oak Swamp and Glendale June 30. Malvern Hill July 1. At Harrison's Landing till August 16. Movement to Fortress Monroe, thence to Centreville August 16-28. In works at Centreville August 28-31, and cover Pope's retreat to Fairfax Court House September 1. Maryland Campaign September 6-22. Crampton's Gap, South Mountain, September 14. Battle of Antietam September 16-17. Duty in Maryland till October 29. Movement to Falmouth, Va., October 29-November 19. Battle of Fredericksburg, Va., December 12-15. "Mud March" January 20-24, 1863. At Falmouth till April. Chancellorsville Campaign April 27-May 6. Operations about Franklin's Crossing April 29-May 2. Maryes Heights, Fredericksburg, May 3. Salem Heights May 3-4. Banks' Ford May 4. Mustered out May 31, 1863, expiration of term. Three years' men transferred to 121st Regiment New York Infantry.

Regiment lost during service 2 Officers and 72 Enlisted men killed and mortally wounded and 2 Officers and 70 Enlisted men by disease. Total 146.

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See also:

• History of the 27th regiment N.Y. Vols, p. 264 [Link].
• Beers Atlas Soldiers List NYVI 27th J-Z - Charles R Leonard 12 October 1861 Priv, 22, Binghamton, NY, Served in Company C, Mustered Out at Elmira, NY on 31 May 1863. [Link]
• New York Civil War Pension Index Cards, Pvt. Charles R. Leonard, Company C, Regiment 27, New York, Arm of Service: Infantry. Source: Organization Index to Pension Files of Veterans Who Served Between 1861 and 1900. NARA Pub #T289, National Archives
• History of the 27th regiment N.Y. vols. Being a record of its more than two years of service in the war for the union, from May 21st, 1861 to May 31st, 1863. With a complete roster, and short sketches of commanding officers. [Link]
• Documents of the Assembly of the State of New York, 1899-1900 [Link]