Gutenkunst.  At the outbreak of the American Civil War, and before regiments of Northern troops had arrived to defend Washington, there was a report of a plot to burn the capital. On April 18, 1861, this report mobilized loyal citizens, including Ferry, and state senator A. Homer Byington, also of Norwalk, to form a militia. This militia was led by Cassius Marcellus Clay, and came to be known as the Cassius Clay Guard.[2][6]On July 23, 1861, he was put in command of the 5th Connecticut Volunteer Infantry, and given the rank of colonel.[7] The original regiment was the 1st Regiment Colts Revolving Rifles of Connecticut and was supposed to be led by Samuel Colt, but the unit never took the field.[8] Its organization failing, the regiment was reorganized in May 1861.[8] In early March 1862, Ferry led his troops across the Potomac River, and attacked the Confederates at Winchester, Virginia.[3] This action would later lead to what became the First Battle of Winchester. Ferry was well praised for his ability as a leader and as a military strategist. Ferry was promoted to brigadier general on March 17, 1862.[7] He was then put under the command of General James Shields, whose division joined that of Gen. Irvin McDowell. It was under McDowell that Ferry fought at the First Battle of Winchester.[3] Ferry continued to serve under Shields, during the Valley Campaign.[9]Battle of Cedar MountainOrris Ferry during the American Civil WarShortly after the First Battle of Winchester, Ferry and the 5th Connecticut Infantry were put under the command of Maj. Gen. Nathaniel Banks.[10] On August 9, Ferry, under Banks, encountered Stonewall Jackson at the Battle of Cedar Mountain.[10] The Union troops attacked to gain early advantage, but a Confederate counterattack repulsed Banks's corps and won the day.[11] Later that day, Union reinforcements under Maj. Gen. John Pope arrived. This led to a two-day stand-off between the two armies. The battle ended in a Confederate victory.[12]Services and resignationDuring the war, Ferry served in the VII Corps, X Corps, and XVIII Corps. He was also the head of the District of Lehigh, from August 20, 1863, until May 1864,[13] and served as the head of the District of Philadelphia from December 16, 1864, until July 15, 1865.[14] Ferry was brevetted a major general of volunteers in recognition of his services during the Peninsula Campaign.[7] He resigned from the military on July 15, 1865.[7] His resignation followed the Confederate surrender.[3]