This Regiment was organized in September, 1861, at Camp Worcester, Monroeville, Huron County, and January 14, 1862, moved to Camp Dennison. In February it proceeded to Jeffersonville, Indiana, and thence to Nashville, Tennessee, arriving there March 18th, and leaving on the 29th for Pittsburg Landing. On the march (April 4th) General Buell detached the First Battalion, sending it to Lawrenceburg, Tennessee, against Biffle's Rebel Cavalry, which was met and driven from the town. The Battalion rejoined the Regiment at Savannah, whence that force moved in advance of Buell's Army, reaching Pittsburg Landing April 25th, going into camp four miles from the River. May 4th the First Battalion went on reconnoissance, marching as far as Monterey, and was ordered to cross Chamber's Creek, where the enemy wa met and driven back to its main force The Regiment then moved within 10 miles of Corinth, where a brisk engagement took place between the First Battalion and a Rebel force, resulting in the retirement of the Battalion. May 27th the Regiment discovered the enemy in force on the railroad west of Corinth, engaged and routed them.

June 1, 1862, the First Battalion was detached to join General T. J. Wood's Division, leaving the balance of the Regiment at Corinth. The Regiment was re-united June 19th, at Tuscumbia, lying there in camp until the 30th, when it went to Mooresville, via Courtland and Decatur. It lay there until July 9th, when the Second and Third Battalions were ordered to Woodville, 30 mile east of Huntsville. July 13th the First Battalion marched to Huntsbille, going into camp there n the 14th. On the 15th the Battalion went to Shelbyville, to defend that Town from apprehended attack; and on the 18th rturned to Winchester. July 29th, Major Foster, with the Battalion and two companies of Infantry, went to Salem, and there captured from the enemy 89 head of cattle.

Leaving Winchester August 14th, the Division and Regiment moved to McMinnville, via Manchester. On the 29th the First Battalion was ordered to cross the Cumberland Mountains to Dunlap, to ascertain the enemy's position. On the way Rebel messengers were captured, bearing dispatches from Bragg to Wheeler, then north of McMinnville. The force then returned to its Division. September 3d the Division marched to Nashville, arriving there the 6th, and the 7th marched to Gallatin. Leaving that point on the 9th on a forced march for Bowling Green, Kentucky, to get ther ahead of Bragg's forces, it arrived there on the 10th, after marching 34 miles per day. The 16th it marched for Munfordsville, encamping at Cave City the 20th. On the 21st the First Battalion had a sharp engagement at Munfordsville with a Rebel force three times its number, and in three charges drove them into their works, losing two killed and 12 wounded, while the enemy lost 38 killed and 60 wounded. Among the Rebel killed was Lieutenant-Colonel Brown. September 22s, the Division marched for Louisville, arriving on the 25th. October 1st the pursuit of Bragg's Army was resumed, and near Beardstwon the First Battalion of the Third Cavalry, re-enforced by two Companies of Second and Third Kentucky Cavalry, attacked the enemy 1,200 strong, but without succes, losing six killed, 20 wounded and 17 captured, Major Foster being among the disabled.

The Second and Third Battalions, under Colonel Zahm, during a portion of the Summer of 1862, were stationed at Woodville, Alabama, guarding a railroad. Repeated attacks by Rebel Guerrillas made this duty one of great activity and fatigue. An expedition under Major Paramore, to Guntersville, on the Tennessee, resulted in driving the Rebel guerrillas from that section, with a loss to the command of six men killed and several wounded, the enemy suffering more severely. For about four months this portin of the Regiment was daily engaged in scouting and skirmishing with the enemy.

The Second and Third Battalions were now attached to the Second Brigade of Cavalry, under Colonel Lewis Zahm, and went into camp at Murfreesboro, Tennessee. This Brigade formed the rear guard of Buell's Army, and guarded its transsportation in the pursuit of Bragg to Louisville. Colonel Zahm was highly complimented by General Buell for his tact in bringing his trains safely through. At Shelbyville the Brigade engaged the advance of Cavalry of Colonel Smith's Rebel Army, drove them from the Town, capturing many prisoners. During the battle of Perryville the Third Cavalry ws engaged with the enemy at the fording of the Kentucky River near Paris; and after that battle it went into camp near Danville. October 19th a detachment of the Regiment under Major Charles Seidel, with a protion of Fourth Ohio Cavalry, in all numbering 250, was sent, under special orders from General McCook, to escort special couriers to Lexington and Covington, a forced march of 40 miles. The force encamped near the old plantation of Henry Clay at Ashland. At daylight, October 20th, the camp was completely surrounded by John Morgan's force, and made to yield to superior numbers. After being stripped of their valuables and dismounted, they were immediately paroled, sent into the Union lines and thence to Camp Chase, Ohio. Private Thomas Crofts, in a letter to his parents, stated that in the fight he was not more than 50 feet from the Rebel ranks. Nearly every horse in the Company ws killed or disabaled. Edwin E. Carr, of Eat Toledo, and Charles H. Colerain, of Toledo, and F. M. Kent, of Bryan, were killed in battle. The forces engaged were 250 Union Cavalry, and Morgan's 3,400 men and eight mountain howitzers. The number of men paroled was 198, beside officers. After the surender Private Weis, of the Third Cavalry, asked to be shown General Morgan, when one among the Rebels was pointed out as the man. Whereupon Weis at once drew up his carbine, and, before he could be disarmed, took aim and shot down the supposed guerrilla leader, who proved to be Charlton Morgan, a cousin of John. Weis was immediately killed by the infuriated Rebels.

The remaining portion of the two Battalions moved from Danville to Bowling Green, and were stationed on the Railroad, with head-quarters at Fountain-Head Station. Morgan's forced then occupied Gallatin. Colonel Zahm ordered out a detachment on a reconnoissance toward Gallatin, to learn the enemy's strength and position, when Rebel pickets were captured and the required information obtained. The next mroning Morgan's camp was attacked and his camp equipage and a large number of prisoners captured, Morgan hastily retreating across the Cumberland to Lebanon, Tennessee. Here after a separatin of seven months, the three Battalions of the Third Cavalry met under novel circumstance. Colonel Zahm, not aware that the First Battalion was in the civinity, on approaching Gallatin frm the North, was attacked by a Cavalry force which turned out to be his own First Battalion, which mistake was probablythe cause of Morgan's escape and the failure of the expedition, the firing between the two forces giving him notice of the presence of Union troops.

From Gallatin the Regiment moved to Hartsville, Tennessee, there going into camp. A detachment, under Captain E.M. Colver, went up the Cumberland River to Carthage to intercept a large drove of mules and Rebel stores; and after a chase of 26 miles--fording the River four times--they captured the train and drove off 146 mules, killing three and capturing 17 of the Rebel escort, including two quartermasters and a paymaster. I December this portion of the Regiment moved to near Nashville and were incorporated into the Second Brigade f Cavalry, First Cavalry Corps, Army of the Cumberland, under Genera D.S. Stanley. The First Battalion of the Third now rejoined the Regiment. December 26th the Regiment moved up with its Brigade and took ositon on the extreme right of Rosecrans's Army, near Franklin. On the 27th an attack was made on Franklin, resulting in completely routing the Rebel force remaining at that place. On the 28th the Brigade engaged the enemy on Wilkerson Turnpike beyond Triune, and drove them with severe loss, the Brigade losing a few prisoners. At 2 A.M., December 31st, the First Battalion, being on picket duty, apprised Colonel Zahm of the advance of Bragg's Rebel forces. At four o'clock the skirmish-line was driven in and the Brigade attacked by Wheeler's Rebel Cavalry. After two hours' fighting, the enemy, through superiority of numbers, forced the main portino of the Brigade from the field, that command suffering severely in both officers and men. The enemy had captured McCook's Corps ammunition-train, when the Second and Third Batalions, Third Ohio, after withstanding the shock of battle, remained at their posts, made a gallant dash and recaptured the train, killing a number of Rebels and horses, and taking 140 prisoners. On that day the Regiment lost 13 men killed and a large number wounded. January 1, 1863, the Third Cavalry bore an active part in escorting a train of 4,000 wagons from Franklin for Nashville, in doing which fierce contests occurred with Wheeler's Rebel Cavalry.

After the battle of Stone River, the Third Cavalry was sent in pursuit of the enemy, and near Middleton, Tennessee, attacked his rear-guard and captured one of his trains. While in camp at Murfreesboro, a detachment of the Third Battalion, while on a scout, under Lieutenant F. Bernard, was surrounded by Rebels, when they cut their way out, with slight loss, and taking with them a number of prisonrs. About that time the Regiment was in affairs at Milton, Liberty, Readyville, Franklin, Snow Hill, Smithville, Auburn, Manchester and McMinnville, suffering in men killed and wounded and loss of horses.

The Regiment bore an active part in the advance of Rosecrans's Army from Murfreesboro, in July, 1863. During the battle of Chickamauga, it was at Lafayette, where it wa attacked and forced back to Charleston, Tennessee. After the battle, the Third Cavalry moved as the advance of General Crook's forces in pursuit of Wheeler's Cavalry, with which a handsome and successful fight took place at Farmington, the enemy being completely routed, with loss of large numbers in killed and captured. The Third Cavalry lost two men killed and 23 captured. In November, 1863, a portion of the Regiment, under Colonel Seidel, scouted through the mountains of East Tennessee. Another detachment, under Captain Richard D. Wood, was engaged about Dalton, Georgia, when Captain Wood was kiled. About this time an incident occurred which illustrates both the character of the guerrilla warfare which the Union troops were called to meet and the spirit and manner in which it was met. The circumstances of the incident were given at the time, as follows:

Lieutenant-Colonel Howland was then Post Commander at Decherd, Tennessee. A band of about 50 guerrillas suddenly pounced on a Union man's store at Winchester, three miles West, completely emptying it if its contents, which afforded a handsome prize to them. As soon as word of the robbery was received at Decherd, a detail from the Thrid Cavalry was sent after the plunderers; but in consequence of deceptive information given of the route taken by them, they escaped. Not long afterwards, a force, increased to 150, appeared in the neighborhood, when Lieutenant-Colonel Howland sent Company A, Captain Terry, and Company F, Captain George Williams, of Fremont, in pursuit of them. Coming in sight of them, the scamps, using spurs instead of weapons, incontinently fled. The race was a hard one, during which Captain Williams was thrown by his horse and disabled, but Captain Terry and 15 men soon overtook 60 of them, including Colonel Holman, the Rebel officer in command. The enemy made a stand to receive their pursuers; on perceiving which Captain Terry called on his men to prepare for a sabre-charge, which was no sooner said than done, when the Rebel force of four times their number wheeled and ran, again pursued by the little band. The race between these was long and earnest. The speed of their horses was very nearly equal, and although Deal got so near he could touch Holman, he could not get near enough to hit him a fair blow. While thus near, and both horses at their highest speed, the Rebel Colonel drew his revolver and turning around in his saddle fired three times at Deal, the latter each time parrying the weapon with his sabre so as to divert the shot and save himself from injury. Finally, Holman and several others of the band were captured and returned to Decherd. The Rebel leader was warm in his admiration of Sergeant Deal, pronouncing him the brevest and coolest man he had met, and insisting that his (Holman's) revolver should be presented to Deal and he be promoted. These suggestions were so just, that they were strictly carried out, and Sergeant Deal returned to Ohio with Holman's revolver, and on arriving at Columbus received a Lieutenant's commission for his gallantry.

In January, 1864, while at Pulaski, Tennessee, the Third Cavalry re-enlisted. Of the original 1,300, only 400 effective men were then left. On the 4th of February, it left Nashville for Ohio, reaching Camp Worcester, Monroeville, after an absence of two years. Of the Company which left Toledo, only 30 returned, many of them being on detached service when these left Nashville. Owing to a misunderstanding as to the time of their arrival at Toledo, the contemplated reception of the Veterans did not take place; but impromptu steps were taken by the Mayor; a dinner was provided at the McKenster House; a procession of citizens escorted the heroes to the hotel, where the dinner was partaken of.

March 2, 1864, its furlough having expired, the Third Cavalry re-assembled at Monroeville, with nearly 1,000 recruits secured for it, and making its total force over 1,500 men. Proceeding again to the field, it was re-equipped and went into camp at Columbia, Tennessee, with charge of the line of road from Nashville to Huntsville. About the 1st May, as part of Long's Second Brigade of Cavalry, at Decatur, and also at Courtland, Alabama, the Tegiment wa engaged with the Rebel General Roddey's command, which was routed, with the loss of a Lieutenant-Colonel, a Major and upwards of 30 men killed and wounded. At Moulton, Alabama, the Regiment was attacked by the same force in camp before daylight; and although partly surprised it rallied, drove the enemy from the field with slaughter, and pursued it, capturing 25 or 30 prisoners. At Rome, it was given position on the left flank of Sherman'a Army, and particiapted in the engagements at Etowah, Kenesaw Mountain, Noonday Creek, and the crossing of the Chattahoochie River. Being sent to Roswell, Georgia, to destroy the Rebel stores and factories, it there captured 400 factory-girls, who were sent through the lines by General Sherman. At McAfee Bridge (or Shakerock), July 9th, four Companies of the Regiment, under command of Captain E.M. Colver, engaged a superior force of Texan Cavalry, killing a Lieutenant and seven men and capturing prisoners and horses. Subsequently the Regiment took part in the battles of Peachtree Creek and Decatur, and in raids to Covington and Stone Mountain. In the Kilpatrick raid, the Third Cavalry was with the Brigade in the avance to the rear of Atlanta, and destroyed a portion of the Railroad from Atlanta to West Point, losing thereby 48 men. It also took part in the Stoneman raid, under General Kenner Garrard. In each of these raids it suffered severely. In the flanking movement on Jonesboro, the Regiment was in Garrard's Division of Cavalry. After the occupation of Atlanta, it went into camp near Decatur, Georgia, and when Hood's dash was made, the Regiment was sent in pursuit as far as Gadson.

In the first battle of Franklin, the Regiment was on the left of Thomas's forces, and was engaged with the Rebel Cavalry. A portion of the Regiment was engaged in the battle before Nashville. After Hood's retreat, it followed him across the Tennessee into Alabama. It was then engaged in the Wilson raid through Alabama and Georgia; and in the battles of Selma and Mongomery, Alabama; and of Macon and Griffin, Georgia. In the caputre of Selma, Captain Archibald J. Eyster, now of Toledo, was in command of the advance-guard. The Rebel defense consisted of 6,000 troops inside fortifications, General Forrest being in command. The assault was made by 1,600 Union Cavalry under Colonel Long, commanding the Division. Lieutenant-Colonel H.N. Howland, of Third Ohio, commanded the Second Brigade. He subsequently was made Colonel and Brigadier-General by brevet. The Regiment also took part in the chase after Jeff. Davis, in Wilson's command, in which pursuit a detachment went through to the Gulf. At Selma it lost heavily in killed and wounded. Lieutenant D.C. Lewis and other officers were taken prisoners. Lieutenant Lewis, afterwards paroled, was killed by the explosion of the boiler of the Steamer Sultana, near Mamphis. At Macon, Georgia, while on duty, Captain J.S. Clock was murdered by one of the Fourth United States Cavalry.

Under orders from General Geo. H. Thomas, the Third Cavalry turned over its horses and arms at Macon, and was then ordered to report at Nashville for muster out. Proceeding home via Louisville, the Regiment reached Camp Chase, where it was paid off and discharged August 14, 1865, after an active and efficient aservice of four years, lacking 20 days.