Once again, the regiment was mustered in, this time for thirty days' service starting June 16, 1863, and departed for Baltimore on June 17. It was attached to Morris' Brigade, 8th Army Corps, Middle Department, to July 7, and then to the 3rd Division, 3rd Army Corps, Army of the Potomac, to July 15. It was on duty at Fort Federal Hill and provost duty in Baltimore from June 18 to July 5 before being ordered to Frederick, Maryland, on July 5, and picket and outpost duty there until July 14. It reached New York City on July 16. The 7th was on duty during the New York Draft Riots from July 16–21.