His academic career over, Farnsworth joined the armys march to the Utah Territory as a civilian foragemaster. He remained at Utahs Camp Floyd until the outbreak of the Civil War. When his uncle John F. Farnsworth organized and armed the 8th Illinois Volunteer Cavalry, young Elon joined the regiment and was quickly commissioned a first lieutenant. He was popular with the men, who felt that his shrewdness and wit were proverbial. He was tall, slight, stern and pale, and was courage incarnate but full of tender regard for his men. In early 1862, shortly after being promoted to captain, the impulsive Farnsworth heard of a pastor in Alexandria, Virginia who failed to offer the customary prayer for the health of President Lincoln. The young cavalry officer approached the parson and asked him to recite the usual prayer for the presidents health and well being. When the parson refused, Farnsworth demanded that he do so. When he refused again, Farnsworth had him arrested. Several members of the congregation assaulted the young lieutenant, and it took the threat of shooting them to settle the dispute.
Late in 1862, Farnsworth became seriously ill, and was unable to serve in the field for a time. After he returned and performed further good service with the 8th Illinois, Brig. Gen. Alfred Pleasonton selected Elon Farnsworth to serve on his staff during the campaigns of the spring of 1863. He appears to have done well in that capacity. Farnsworth caught Pleasontons eye at the Battle of Brandy Station, when casualties among the 8th Illinois officers left him the senior officer in the regiment, and he returned to the regiment to assume command for the afternoon phase of the battle.
Pleasonton was known as a toady, and he regularly courted the favor of his political patron, John F. Farnsworth, now an influential Congressman who still held the rank of brigadier general. Perhaps in an effort to curry favor with the elder Farnsworth, Pleasonton wrote on June 23rd, Captain Farnsworth has done splendidlyI have serious thoughts of having him made a brigadier general I am sadly in want of officers with the proper dash to command cavalryhaving lost so many good onesDo assist us until we can get ahead of the Rebs.. The young captain was not above using political influence to promote his career. In a letter to his uncle written on June 29, 1863, the cavalryman wrote: The general speaks of recommending me for Brig. I do not know that I ought to mention if for fear that you will call me an aspiring youth. I am satisfied to serve through this war in the line in my regt as a Capt on Genl Pleasontons staff. But if I can do any good anywhere else of course small favors &c. Now try and take this into the President, and you can do an immeasurable good.
This tactic was successful, because along with Merritt and Custer, Elon Farnsworth was promoted from captain to brigadier general of volunteers on June 28, 1863, and took command of a brigade of cavalry under Kilpatrick.
He did not have long to wait before an opportunity to prove himself in command presented itself. On the morning of June 30, Kilpatrick ran into J.E.B. Stuarts cavalry in the town of Hanover, Pennsylvania, twenty-four miles from Gettysburg. There, a nearly day-long battle raged in the streets of the town, with Farnsworth leading the decisive charge that drove the Confederates out of the town. Two days later, Kilpatrick and Stuart tangled again at Hunterstown, Pennsylvania, where Farnsworth joined Custer and his brigade in attacking the brigade of Confederate Brig. Gen. Wade Hampton. A few of his troopers may have reached Gettysburg late in the afternoon of July 2 in time to assist in the repulse of the Confederate assault on Little Round Top. In the short time he wore a generals star, Elon Farnsworth proved to be an inspirational leader of men who was not afraid to lead charges. This trait would soon cost him his life.
On the afternoon of July 3, after the repulse of Picketts Charge, Brig. Gen. Judson Kilpatrick ordered a mounted charge by Farnsworths Brigade. Over the vigorous protests of Farnsworth, Kilpatrick persisted. He challenged Farnsworths honor and courage, prompting Farnsworth to agree to lead the charge. Crashing out of the woods on Bushmans Hill, his small column was repulsed from the main Confederate line of battle, turned off, rode around the Slyder Farm, and up the side of Big Round Top. There, in a D-shaped farm field, Farnsworth met his fate. Men of the 15th Alabama Infantry shot him down. He was a bold and fearless, who died needlessly in a gloriously futile charge akin to that of the famous Light Brigade. He was a bold and fearless rider. Warner, p. 148.
Faculty Minutes of the University of Michigan for May 3, 1858, copy in files at Gettysburg National Military Park; Manuscript by Col. John B. Bachelder, General Farnsworths Death, copy in files, Gettysburg National Military Park. This account indicates that Two years later, the University was shocked by the news of a wretched carousal in which this young man was a leading spirit. One of the students lay dead at the coroners rooms. Eight students were expelled, among them this man. On leaving the University he went to [Dr. Andrew D.] White [professor of history] and thanked him for what he had done for him, acknowledged the justice of the actions of the faculty, but expressed the hope that he would yet show that he could make a man of himself. Five years later that student fell at the head of his brigade at Gettysburg. It was Farnsworth. He made good his promise. There is no verification of this story available, other than this account.
Abner N. Hard, History of the Eighth Cavalry Regiment, Illinois Volunteers, During the Great Rebellion (Aurora, IL:: privately published, 1868), p. 56.
Henry C. Parsons, Farnsworths Charge and Death, included in Robert U. Johnson and C.C. Buel, eds., Battles and Leaders of the Civil War, 4 vols. (New York, 1884-1888), 3:395. Hard, pp. 76-77.
Hard, Eighth Regiment, p. 202.
Alfred Pleasonton to Brig.Gen. John Farnsworth, June 23, 1863, Alfred Pleasonton Papers, Manuscripts Division, Library of Congress, Washington, D.C.
Elon J. Farnsworth to John F. Farnsworth, June 29, 1863, Pleasonton Papers.
William C. Oates to Joshua L. Chamberlain, April 15, 1905, Trulock Collection, Pejepscot Historical Society, Brunswick, Maine. Oates stated, when my men were retreating they encountered a thin line of dismounted cavalry men through which we ran and took two or three of them out as prisoners. About that I am not mistaken. They belonged to Kilpatricks cavalry and we encountered them near the foot of Big Round Top, but made no halt, ran right through them and my men took two or three of them, as above stated, as prisoners, and from them we learned the command to which they belonged.