15th New York Infantry Regiment

June 17

Organized at New York City and mustered in for two years' service

June 29

Left State for Washington, D.C. and duty as Infantry in the Defenses

July 30 to August 4

Attached to McCune's Brigade and Franklin's Brigade, Division of the Potomac

September 26

Attached to Newton's Brigade

October 25

Designation of Regiment changed to 15th New York Engineers