[6] Eight companies were mustered into the State service by Maj. Robert Taylor, Monday, April 22, 1861, on which day Edward McK.

On Wednesday, May 8, 742 United States percussion muskets, pattern 1848, calibre 69, were issued to the regiment by Commissary General Welch.

[6] To assist in the organization of the Regiment the Union Defense Committee of New York city expended $3,987.16.

[6] At the end of their term of service, the regiment returned to New York city, where they were honorably discharged May 25, 1863.

On that day, it was sent to Havre de Grace, MD, at the mouth of the Susquehanna River and the head of Chesapeake Bay.

[6][11][note 6] After Antietam, the 4th was part of the force sent to reoccupy Harper's Ferry on Monday, September 22 as the Rebels had withdrawn to the Rappahannock.

[6][12] It remained in the garrison there for five and a half weeks until October 30, when it marched down to Falmouth with the army arriving opposite Fredericksburg on November 17.

Unknowingly moving toward an overwhelming Rebel force, Gen. Hooker recalled it back to Federal lines before contact.

Upon return to the main body of the army, the 4th was detailed to special duty guarding the II Corps hospital.