The One Hundredth, or as it was more commonly known, the Round Head Regiment, was recruited in the south-western counties of the State, originally settled by the Round Heads of the English Revolution, and by Scotch Irish Covenanters. Daniel Leasure, a citizen of New Castle, who had since 1832 been connected either as private or an officer with the State militia, and who, during the three months' campaign, had served as Captain and Adjutant of the Twelfth Regiment, received authority from the Secretary of War, under date of August 6, 1861, to recruit a regiment of infantry from among the descendants of the Covenanters and of the men who had followed Cromwell, whose leading characteristics had been a devotion to the principles of liberty of person and of conscience.

On the 2d of September the regiment, which had been recruited to the number of twelve companies, was ordered to Washington, whither it at once proceeded, and upon its arrival encamped on Kalorama Heights. A formal organization was soon after effected, and the following field officers were selected and commissioned: Daniel Leasure, Colonel; Captain James Armstrong, Lieutenant Colonel; Captain David A. Leckey, Major.

Just previous to the organization, General Casey, in command of provisional brigades at Washington, issued an order transferring companies L and M to the One Hundred and Fifth Regiment. Company L was accordingly thus transferred, and Captain Dick, its commander, became Major of that regiment; but upon the representation of Captain Leckey that his men had been specially recruited for the Round Head Regiment, company M was permitted to remain. It was brigaded on the 7th of October with the Eighth Michigan; Colonel Fenton, and the Fiftieth Pennsylvania, Colonel Christ. As the ranking officer, Colonel Leasure was placed in command of the brigade, and was ordered to proceed with it to Annapolis, there to join the command of General T. W. Sherman, destined to the coast of South Carolina. Soon after its arrival, Colonel Leasure sent a request to the Secretary of War, in behalf of the Round Heads, that the Highlanders, Seventy-Ninth New York, might be associated with them in the same brigade. This request was granted, and on the 12th General Isaac I. Stevens was assigned to its command. On the 19th the fleet sailed from Annapolis and rendezvoused at Fortress Monroe, whence on the 29th it set sail with sealed orders.

The Round Head Regiment and five companies of the Fiftieth Pennsylvania were embarked together on the Ocean Queen. On the second day out the fleet was overtaken by a violent storm, which raged with unabated fury for thirty-six hours. On the morning of the 3d of November, all the other vessels of the fleet being out of sight, Colonel Leasure opened his orders and read, " Sail for Port Royal Entrance," which was the first intimation to any one on board of its destination. On the 5th of November the fleet arrived off Port Royal Entrance, and the gun-boats proceeded to make soundings of the channel. On the morning of the 7th the transports stood in for the entrance, and the gun-boats advanced to the attack of Forts Walker and Beauregard, on the opposite points of Hilton Head and Lady's islands. The troops, meantime, were held in readiness to debark and attack by land; but at three o'clock P. M. the enemy was driven from his works by the terrible broadsides of Dupont's powerful vessels, and fled to the main land or adjacent islands. On the same evening the troops landed and took possession of the forts and islands. Strong fortifications were at once begun, for which heavy details were made on the troops of General Stevens' Brigade, who soon experienced much sickness from fatigue, and the process of acclimation to the delightful but malarious climate of a southern coast. One month later General Sherman resolved to occupy a point farther inland, upon the net work of islands which the capture of Port Royal Entrance, on the 7th of November, had made accessible to the Union gun-boats. General Stevens was detailed with his brigade for this purpose. The pleasant town of Beaufort was taken possession of, and occupied as headquarters. The chief military duty of the troops, for the next five or six months, consisted in picketing Barnwell's and Port Royal islands, on the Coosaw, across which on the main land, upon the "Shell Road" leading to Charleston, a Rebel force was stationed, covering the approaches to the railroad connecting Charleston and Savannah. The town of Beaufort, with Port Royal and all the adjacent islands, had been deserted by the white population since the battle of November 7th. To repress the boldness of the enemy in his hostile demonstrations at Port Royal Ferry, on the morning of the 1st of January, 1862, General Stevens, with a force of infantry and artillery, acting in conjunction with two gun boats, crossed the Coosaw, drove the enemy from his unfinished earthworks, and returned on the following day to the ferry without loss. During the occupancy of Beaufort and while at Hilton Head, many sickened, and some died, among them Lieutenant James L. Banks, of company F.

General Hunter, who had now relieved General Sherman in command of the Department, undertook the reduction of Charleston. On the 1st of June General Stevens, with the Round Heads, Highlanders, and the Eighth Michigan, proceeded through Stono Inlet to James Island, effecting a landing near Legarev-lle. Five companies, A, F, D, I, and H, of the Round Heads, were on the advance vessel with General Stevens, the six remaining companies, under Colonel Leasure, following immediately after. Companies D and H seized the village, while the remaining forces moved up the island. The enemy was driven from his works and all his shore batteries captured. Two heavy guns were subsequently taken in the interior of the island by companies A, F, and I, and brought in. The regiment lost in this engagement about twenty killed and wounded. Captain Cline, of company F, and fifteen men, were captured while skirmishing without proper supports. Until the 15th, the regiment was engaged in erecting forts and in performing guard duty, and was almost constantly under fire from the enemy's forts, lying in the meanwhile under shelter tents in a low marsh, barely above tide water, and in constant expectation of being attacked.

At evening on the 15th of June, the troops upon the island were ordered to be in readiness early on the following morning to attack the enemys works at the Tower Fort, near Secessionville, a strong earthwork held by the Rebel Colonel Lamar with a strong force, and commanding the approaches to Charleston. by the James Island causeway. General Stevens was to attack, and General Wright to support on the left, and if need be, assault the work on tho north. Colonel Leasure was placed in command of a brigade composed of his own, the Seventy-ninth and Forty-sixth New York.

At two o'clock on the morning of the 16th the troops moved out for the attack. An unaccountable delay occurred, and the attacking party was not formed until broad daylight. Colonel Fenton's Brigade, which led the assaulting column, was swept and broken by a destructive fire, and Colonel Leasure's, which supported it, was soon in the forefront. After a severe contest, lasting nearly an hour, during which a number of both the Highlander and the Round Head regiments forced their way into the fort, Colonel Benham, in chief command, ordered a retreat. The narrow neck of ground over which the troops must advance was barely sufficient to deploy one regiment, and this was swept by the guns of the fort and from the rifle-pits and defences in the rear. Of the four hundred and twenty-one officers and men of the regiment who went into the fight, one officer, Lieutenant Samuel J. Morrow, and eight enlisted men were killed, two officers and thirty men wounded, and six missing. General Stevens, in his official report, says: "Colonel Fenton, in command of the First Brigade, used every exertion to throw the Eighth Michigan as far to the right as possible, and to bring on, in support, the Seventh Connecticut, and the Twenty-eighth M1assachusetts; but the terrible fire of grape and musketry from the enemy's works cut the two former regiments in two, the right going to the right and the left to the left, whither, finally, the whole of the Twenty-eighth Massachusetts took its position, and where they were joined, with scarcely an interval of time, by the One Hundredth Pennsylvania and the Forty-sixth New York, of Leasure's Brigade. These regiments had been brought up with great promptness and energy by Colonel Leasure, and the right of the One Hundredth had pushed up to, and joined the Seventy-ninth in the charge. It was during this brief period, of less than one-half hour-from five to halfpast five o'clock-'that the greater portion of the casualties occurred. * * "I must express my profound sense of the intrepid bearing and soldierly conduct of my brigade commanders, Colonels Leasure and Fenton, who did everything that commanders could do to lead their respective brigades to the attack; and it is mainly due to their exertions that their lines of battle were maintained throughout the action."* Lieutenant Jefferson Justice, serving upon the staff of General Stevens, and Lieutenant S. G. Leasure, Assistant Adjutant General to the brigade, were commended for their gallantry. After the battle, the hospitals, crowded with the wounded, stood in urgent need of immediate surgical aid. Colonel Leasure, whose profession was that of medicine and surgery, at once volunteered, and rendered most valuable assistance to the young surgeons in charge.

Operations against Charleston having been suspended, an evacuation of the island was ordered, and on the 4th of July the brigade returned to Hilton Head, where, among the accumulated mails, were the commissions for the officers, from Governor Curtin, and an order declaring the Round Head Regiment the One Hundredth of the line. Lieutenant Colonel Armstrong, who had been in a feeble state of health from disease contracted in the service in Mexico, aggravated by a semi-tropical climate, was forced to resign, and was succeeded by Major Leckey, Captain Matthew A. Dawson being promoted to Major. On the 13th, the brigade returned to Beaufort, and soon after its arrival there was ordered to Virginia, whither it proceeded on the ocean steamer Merrimac, then on her trial trip. It went into camp at Newport News, where it was visited by a messenger from Governor Curtin, bearing the State colors, which were presented t tthe regiment by General Stevens, and were received in a patriotic speech by Colonel Leasure.On the 4th of August, the regiment was moved by transport to Acquia Creek, and thence by rail to Fredericksburg, where the troops under General Stevens from South Carolina, and those from North Carolina, under General Burnside, were united, and were placed under the command of General Reno, subsequently known as the Ninth Corps. Pope's army of Northern Virginia, consisting of the corps of Banks, Sigel, and lIVDowell, holding the left bank of the Rapidan, was threatened by the concentrated rebel army, and all available forces were being pushed on to his assistance. On the 13th, Stevens moved forward, and at Raccoon Ford was brought to a stand to dispute the passage of the enemy. After holding the position for three days, General Reno, who had now come up with the balance of his corps, having discovered that the enemy, in greatly superior numbers, was in his front, decided to withdraw, and at mid-night of the 19th, leaving the ford heavily picketed, retired to the line of the Rappahannock, crossing at Ely's Ford.

Then commenced a series of marches and counter-marches, disputing the passage of the fords of the Rappahannock, which continued until Stonewall Jackson made his famous move to Manassas Junction, in the rear of the Union army, when Reno's Corps started in pursuit, being joined on the way by the division of Kearny. From Greenwich the command followed to the old Bull Run battle ground, where it encamped on the evening of the 28th. At four o'clock on the following morning it moved forward, and after passing through rocky and wooded by-ways, forded Bull Run and debouched into the open ground to the south of Centreville. Here, about two hundred Union soldiers, captaured and paroled by Jackson, were met, who gave information of the proximity of the rebel force. At eight o'clock, Stevens' Division was divided, one brigade, under Colonel Christ, being sent to the support of Kearny, one under Colonel Farnsworth, to support Miilroy, and the third, under Colonel Leasure, to the assistance of Sigel. General Stevens remained with Colonel Leasure, remarking that' it would be the fighting brigade that day." It was composed of the One Hundredth, under Colonel Leckey, and four companies of the Forty-sixth New York, under Colonel Rosa, the remaining five companies of this regiment being detached for train guards.

At half-past ten A. M., when Sigel, who had borne the brunt of battle since early morn, was nearly outflanked, and the enemy was preparing a new attack against his centre, Kearny's and Stevens' divisions came to his aid. By direction of General Stevens, Lieutenant Benjamin's Battery of twenty-pounder Parrott's relieved Captain Dilger's Battery, on the crest of a hill, immediately on the left of the Warrenton Turnpike, and simultaneously Colonel Leasure's two regiments were deployed in line of battle for its support. The enemy was checked, and companies A, F, D, I, and M, of the One Hundredth were sent forward as skirmishers, taking position in the valley a quarter of a mile in advance, and keeping up a galling fire, Benjamin's guns in the meantime throwing shot and shell over their heads. The enemy seemed determined to carry that position, and at one time five batteries were concentrating their fire upon it. But Benjamin steadily held his ground until his ammunition began to fail him. In taking position, one of his caissons, well filled, had been accidentally overturned and abandoned, at a point about two hundred yards to the left and front of his present position, much exposed to the enemy's fire. Company G, Captain S. H. Brown, was ordered to bring it up. With intrepid daring it was led under the enemy's fire, and brought the heavily laden caisson, now sorely needed, safely off. Benjamin now increased his fire, and soon silenced a number of the enemy's guns. But one of his own had been struck by a solid shot and rendered useless, and another, by the premature explosion of a shell, had been disabled, and still another had lost nearly all its men. But until his ammunition was all spent, the remaining guns were kept in play. They were then withdrawn, and soon after the only remaining division of Sigel, on the left, fell back. Stevens was then ordered to retire. In the face of a terrible fire, now re-doubled, it was with difficulty that the skirmishers could be withdrawn, but was successfully accomplished under the direction of Lieutenant Gilleland. The enemy, now no longer deterred by the battery's fire, moved heavy masses of infantry obliquely in front of its late position across the Warrenton Turnpike, and gained a most important position in a piece of wood, where the heaviest fighting occurred in the after part of the day, in which, with other troops, the One Hundredth suffered fearful loss. Leasure's Brigade had not retired a quarter of a mile, when it was ordered to the support of Roemer's Battery, on the north side of the turnpike, in an orchard somewhat to the rear of the former position. It was now nearly night, and the troops had suffered severely. They had scarcely reached their position, when an order came from Reno directing Stevens to support Kearny, who was enveloped in the woods to the right, on the line of the abandoned track of the Gap Railroad. Stevens had but this small brigade, the rest of his division having been ordered from him early in the day; but no time was to be lost, and moving off by the right flank at double quick, Colonel Leasure put his command in position for a charge. At that instant General Kearny came dashing up and demanded of Stevens where his troops were. Stevens pointed to the barely five hundred that stood about him. In his abrupt way, Kearny asked if they would fight. "Yes," said Stevens, with an oath, " these are my Round Heads." Dropping his bridle rein, with an impetuous gesture, in the direction of the enemy, with his only arm, he said to Colonel Leasure, " Sweep everything before you." Companies A and B of the One Hundredth were thrown forward as skirmishers, and the line quickly put in motion towards the low wooded ground where the enemy lay concealed. As they advanced, artillery and infantry were opened upon them, which told fearfully on their already shattered ranks. As the line approached, a well directed fire was poured upon the enemy, before which he recoiled. At this juncture an aid from General Kearny came up, and informed Colonel Leasure that the enemy was occupying a cut in the old Gap Road a short distance to the front, and to the left of the position he then held. Obliquing to the left, the line charged, and as the enemy scrambled up the opposite bank of the cut, it poured in a destructive fire and seized the abandoned position. Soon the enemy opened a heavy fire. General Stevens' horse and that of his orderly were both killed. Seeing that it was useless to attempt to hold the position against the overwhelming force that wearing down upon him, he ordered Colonel Leasure to fall back before the way was completely cut off. The order was accordingly given, and as he was moving, the Colonel had his horse shot under him, and himself received a painfull wound. Of the four hundred and fifty who had joined in this last charge, but one hundred and ninety-eight came back unhurt. Captains William F. Templeton, Simeon H. Brown, James S. Van Gorden, and Lieutenants Philo P. Payen and E. J. R. Spencer were killed or mortally wounded, and Lieutenants John P. Blair and Thomas H. Curt were severely wounded.

Taking up a new line, the command was soon after joined by the other brigades of the division, and rested on its arms during the night. Colonel Lersure and Major Dawson having both been wounded and sent to hospital, the command of the brigade devolved on Lieutenant Colonel Leckey, that of the regiment on Captain James E. Cornelius. Early on the morning of the 30th, the battle was renewed, and continued, with varying suocess, during the day; but the Union army was finally forced to retire before the overwhelming numbers of the enemy, and at night fell back to Centreville.

The following day was the Sabbath. The fight was not renewed. Lee was too cautious to attack Pope on the heights of Centreville, but ordered Jackson, with his corps, to pass around the Union alrmy, and attempt to cut its communications with Washington. The objective point of the movement was Fairfax Court House, but Jacksons advance was met and hurled back at Ox Hill, near Chantilly, while yet several miles distant from that place. Pope, aware of Jackson's movement, had on Monday, September 1st, massed several corps in the vicinity of Fairfax Court House, and pushed Reno northward, toward Chantilly, in the direction of Jackson's advance. The One Hundred had been hastily marched out of bivouac, and now at five o'clock formed, advancing in column through a meadow, then a wood, the Forty-sixth New York following, and the Seventy-ninth New York skirmishing in advance. Emerging from the wood into a field but partially cleared, the column encountered a rapid fire of musketry from the enemy. General Stevens, dismounting, hastily formed his lines of battle in person, and promptly drove the enemy back beyond the partially cleared ground, and into the edge of a field of corn. In these two fields the battle was fought. Jackson's entire corps was in line of battle in front, Reno's Corps, now reduced to two slender divisions, being much inferior in numbers. General Kearny, however, with a part of his division, was in the rear. In fifteen minutes after the action began, General Stevens, while forming the Seventy-ninth New York in line of battle, was instantly killed by a musket ball in the head. Shortly after, a furious rain began to fall, accompanied with thunder and lightning. By this time General Birney, with four regiments of Kearny's Division, had been ordered in, and the enemy was driven back still farther through the corn. General Kearny, riding up to the One Hundredth, now without ammunition, asked support for a battery. The men responded with a cheer. The battery (Randolph's) was placed in position and brought to bear over the heads of Birney's men, though the darkness prevented any accuracy of aim. A few minutes later General Kearny, while reconnoitring, rode into the enemy's lines, and asking, " What troops are these," discovered his mistake, but received a fatal bullet after he had turned his horse's head and was galloping away. As he did not return, General Birney, presuming he had been captured, assumed command and gallantly maintained the action, pushing forward two fresh regiments, the Thirty-eighth New York and Fifty-seventh Pennsylvania. Our troops remained in possession of the field and kindled fires, which the cold rain had rendered especially necessary. The action was now over. Before day the field was evacuated by our victorious regiments, which with the entire army fell back upon Washington. Captain Cornelius, in command of the regiment, was severely wounded, and after suffering for a long time was discharged on account thereof. Captain R. J. Ross and Lieutenant Samuel R. Grace were wounded. The loss was two killed and thirty-four wounded.

The invasion of Maryland followed close upon the defeat of Pope in Virginia. In the battle of South Mountain, on the 14th of September, the regiment participated, and in the charge up the mountain suffered severely, losing eight killed and twenty-eight wounded. In the battle of Antietam, on the 17th, having lost nearly all its line officers, it was not actively engaged. After advancing as skirmishers until the battle had opened, it was relieved and held in reserve during the rest of the day. Its loss was one killed and four wounded. On the 18th, Morell's Division of Porter's Corps relieved Reno's late command, the latter retiring, and on the 19th encamping near the mouth of Antietam Creek. On the 11th of October the brigade, which now consisted of the One Hundredth, the Forty-fifth Pennsylvania, and Thirty-sixth Massachusetts, was sent to Frederick City to intercept the rebel General Stuart on his raid to Chambersburg, but was unsuccessful. Soon afterwards Colonel Leasure, who had now returned from hospital, was sent to Washington, by General Burnside, to bring up the absentees and convalescents of the Ninth Corps, assembled in camp near the city. About four thousand were thus added to its strength, two hundred of whom belonged to the One Hundredth Regiment. In November, soon after the return of the army to Virginia, General W. W. Burns was assigned to the command of the division, and Colonel Leasure, who had temporarily held command, returned to his brigade.

On the 19th of November, the corps arrived opposite Fredericksburg and went into camp. On the following day the regiment was sent to construct a corduroy road upon the way leading to Belle Plain, the base of supply, returning on the 25th. The Ninth Corps now formed part of the right grand division of the army, commanded by General Sumner. On the 12th of December the regiment crossed the river, and with the corps occupied the city of Fredericksburg. Burns' Division was assigned to the support of Hancock, and was afterwards sent to the assistance of Franklin, on the left.

During the progress of the battle on the 13th, the division lay in reserve awaiting the order to advance, which was momentarily expected. At midnight, Colonel Leasure was directed to move his brigade to position on the left of General Stoneman, which was promptly done, but at daylight returned again to its former position. The battle was not renewed on the 14th. At dusk, on the 15th, Colonel Leasure was ordered to send his most reliable skirmish regiment to report to General Sumner. The One Hundredth was selected. It was pushed forward towards the enemy, and deployed to cover the retreat. But so quietly and skilfully was the withdrawal accomplished, that the suspicions of the enemy were not aroused, and the troops all crossed in safety without molestation. Near the close of the year, Lieutenant Colonel Leckey resigned, and was succeeded by Major Dawson.' Captain James H. Cline was subsequently promoted to Major.

Early in the year 1863, General Burnside was placed in conmmand of the Department of the Ohio, and two divisions of his old corps were ordered to Kentucky to report to him. Rendezvousing at Fortress Monroe, these divisions proceeded via Baltimore, Parkersburg, and Cincinnati to Lexington, Kentucky, where the One Hundredth arrived on the morning of the 28th of March. After remaining in camp a week, the regiment moved to Camp Dick Robinson, and was subsequently at Middleburg and Columbia. While at the latter place General Wmelsh was assigned to the command of the division, and the brigade was re-organized and made to comprise the One Hundredth Pennsylvania, Seventy-ninth New York, Second, Eighth, and Twentieth Michigan.

Early in June the corps was ordered to the support of Grant at Vicksburg, and embarking at Louisville upon transports proceeded to Young's Point, on the Mississippi, but shortly after returned to Snyder's Bluff, and debarking, marched to Milldale Church, in rear of the besieging army, and took position facing towards the Big Black, where the rebel General Johnston had collected a large force, with the design of raising the siege and relieving the beleaguered garrison. As soon as the forces were settled in camp, details were made for fatigue duty in felling timber and intrenching the position. On the 29th the command moved some ten miles further out and took position at Flower Hill Church, to guard the fords of the Big Black, where it remained until the ever memorable 4th of July, when Vicksburg was surrendered. General Sherman immediately moved with a part of Grant's forces and the Ninth Corps to attack Johnston, who had fallen back to Jackson. Bridging the Big Black, the First Division crossed at four o'clock on the afternoon of the 4th. On the 10th, the advance entered the enemy's picket lines near the Insane Asylum, just out of the city. Line of battle was formed, and advanced to within three hundred yards of the enemy's works. The brigade held the extreme left, its left resting on the Pearl River, where it was exposed to an enfilading fire freoul the enemy's batteries. This position was held until the night of the 13th, when the brigade was relieved by the Fourth Brigade. The loss in the command during this time was considerable, the men being obliged to remain prostrate upon the ground, many a poor fellow being struck dead where he lay. On the morning of the 17th, it was discovered that the enemy had evacuated, when the city was quickly occupied by the Union troops. On the morning of the 18th, the brigade marched to Madison Station, where it was engaged in destroying the railroad. Upon its return, it moved with the corps back to its old camp at Milldale. The campaign, though short, had been sharp, the heat of the weather added to the fatigue and anxiety experienced, and worse than all, the abominable water of the Yazoo and the Big Black, telling fearfully upon the health and spirits of the men. From Vicksburg the corps, now under command of General Parke, was ordered to East Tennessee. Moving by boat to Cairo, the regiment proceeded by rail to Cincinnati, and thence to Camp Nelson, in Kentucky. While here, many of the men were attacked with a fever of a malarious congestive type, of which many died, among them Commissary Sergeant, James Henderson. When the division started on the 25th of September for East Tennessee, one fourth of the men in the regiment were left in hospital, and many of those who moved with the column were greatly enfeebled by disease. At Blue Spring the enemy was met, and a brisk engagement ensued, in which his intrenched position was carried and his forces scattered. From Knoxville, to which place the troops soon after returned, the division marched to Lenoir Station, on the East Tennessee and Virginia Railroad, where the regiment went into camp and erected comfortable quarters. It was hardly settled before Leasure's Brigade was ordered, by telegram from General Burnside, at Knoxville, to proceed thither without delay, the enemy having attacked and captured some troops of the Twenty-third Corps, and further trouble being anticipated. It was evening when the order was received, and at day-break on the following morning it had arrived and reported for duty to the commanding general. Its services, however, were not needed, and for four days, from the 6th to the 10th of November, the troops were held in waiting, exposed to intense cold, without shelter tents. At the end of that time it returned to its camp at Lenoir, but on the morning of the 14th it was ordered to return, with all possible dispatch, to Knoxville, Longstreet having crossed the Tennessee at Kingston, and now threatening to cut off the troops south of the city. Seven companies of the One Hundredth were detailed as escort to the division train, which was immediately put in motion, and the remaining three, A, F, and D, under Captain Hamilton, were detailed to remain and destroy government property at Lenoir. The Union troops reached Campbell's Station first, and a stand was made which enabled the trains to reach Knoxville in safety. Entrenchments were hastily thrown up for the defence of the city, and on the morning of the 17th, the troops had all arrived and were in position. Longstreet laid siege and closely invested the place. Frequent charges and assaults were delivered by the enemy, but without advantage, and on the morning of the 29th, a grand assault on Fort Saunders, the principal work, defended by the First Division. With determined bravery his troops advanced, some of them reaching the ditch in its front, but were finally repulsed with great slaughter. The siege was continued until the 4th of December, when, learning that General Sherman was coming up on his rear with a strong detachment from Grant's army at Chattanooga, Longstreet retreated towards Virginia, and the garrison, which was suffering for want of provision, was relieved.

On the 9th of December, the command marched to near Rutledge, and on the 18th to Blaine's Cross ioads. On the 1st of January, 1864, while subsisting on less than two ears of corn a day per man, the entire ragiment, with the exception of twenty-seven, re-enlisted to the number of three hundred and sixty-six, for a second term of three years, and immediately started for home on a veteran furlough. The mid-winter march over the Cumberland Mountains was very severe, many of the men being bare-foot and without adequate clothing, no supply trains having reached Knoxville during the continuance of the siege. At Cincinnati the regiment was paid, and on the 8th of February reached Pittsburg, where the men were dismissed to return to their homes.

On the 8th of March the veterans rendezvoused at Camp Copeland, near Pittsburg, and with them a sufficient number of recruits, who had been gathered in during the brief furlough, to raise its combined strength to nine hundred and seventy-seven men. A few days later, the regiment proceeded to Annapolis, Maryland, the rendezvous of the Ninth Corps, where it was brigaded with the Twenty-first Massachusetts, and the Third Maryland, forming the Second Brigade of the First Division, and Colonel Leasure placed in command. Leaving Annapolis, the brigade reached Bealton Station on the 2d of May, and having moved with Grant's army to the Wilderness, on the night of the 5th was placed on picket. At daylight on the following morning it was relieved and ordered to duty as guard to the corps artillery. The Ninth Corps was an independent command, and was regarded as a reserve to the army; but the enemy attacking in great force, it was ordered in, and the brigade, which was in rear of the artillery, was directed to pass it, and report to General Hancock, of the Second Corps. It was posted by General Mott, of that corps, in breast-works thrown up near the Brock Road; but soon afterwards, Colonel Leasure was directed to lead his brigade over the works, into the dense woods in front, find the enemy's position, and if possible, attack him in flank. The first onset of the day was now over, and each side seemed content to rest on its arms and re-adjust the shattered lines. As the brigade moved over the recently contested ground, the dead and wounded of both sides lay thickly strewn on every hand. The forest had been fired, the flames, consuming and devouring the dry leaves, was rapidly approaching them. The skirmish line, which was a few paces in front of the line of battle, advancing at a trail arms, discovered the enemy approaching, but before the command could deliver its fire, his line about faced and moved rapidly out of sight. The brigade immediately changed front to the left, and marched to meet a flank movement of the enemy in that direction, but on discovering our troops advancing, he again fell back, and it moved on in the original direction. After pushing a half mile through the dense underbrush, it was discovered that the enemy had retired to his earth-works, where he was awaiting an attack. The object of the reconnoissance having been accomplished, it returned and was warmly complimented by General Hancock for its efficient service. Much exhausted, it was led back a little in rear of the line of breast-works, where it rested. At four o'clock in the afternoon, the enemy suddenly opened a furious attack upon the line a little to the left of the point where the brigade was lying. In a short time the breast-work, which was made of dry logs and rails, was fired by the enemy's shells, and instantly blazed up, making the ground untenable, and the troops occupying them fell back. Seeing this, other troops further to the right were seized with a panic and retreated in confusion, the enemy occupying the abandoned works. At this juncture, Colonel Leasure ordered the One Hundredth, and the Twenty-first Massachusetts, to charge, and following up with the Third Maryland, routed the enemy and re-captured the lost works, securing many prisoners and several stands of colors. The losses in the One Hundredth were fortunately light; Captain J. H. Pentecost was severely wounded in the final charge. The brigade remained in possession of the captured works until the following afternoon, when it was relieved and re-joined the division.

On the 9th, the corps crossed the Ny River, and took position in front of Spottsylvania Court House, where General Stevenson, in command of the division, was killed. Colonel Leasure was directed to assume command and push the enemy back towards the Court House, which was accomplished with only small loss. On the 12th, the fighting was renewed, and continued during the entire day and far into the night, falling heavily upon the Ninth Corps, the One Hundredth Regiment sustaining considerable loss. In the severe engagements at the North Anna, on the 28th of May, and at Cold Harbor, on the 2d of June, the regiment participated, and in the latter, Lieutenant David J. Gillian was killed.

After crossing the James, the regiment was warmly engaged in the series of battles in front of Petersburg, prelude to the siege, in which Captain Leander C. Morrow was killed, and Lieutenant Colonel Matthew M. Dawson was mortally wounded. The mine, which was exploded on the 30th of July, had been excavated within the lines of the Ninth Corps, and in the movements which were immediately inaugurated the regiment participated, in which Captain Walter C. Oliver, and Lieutenants Richard P. Craven and Samuel G. Leasure were killed, and Major Thomas J. Hamilton, in command of the regiment, was mortally wounded and taken prisoner.

On the 19th of August, the enemy attacked the Union forces while occupying a position upon the Weldon Railroad, and pushing his way through between the lines of the Fifth and Ninth Corps, achieved some success. In this encounter the One Hundredth was engaged, and again on the 21st, when the enemy made a determined effort to dislodge the Fifth Corps, but was finally foiled in his attempts. On the 30th of September the lines were again extended to the left, and at a point near Poplar Spring Church two strong forts, a mile and a half of rifle-pits, and two guns, were captured. The enemy finally flanked a division of the Ninth Corps, and a severe struggle ensued. The regiment fortunately sustained only small loss. In the movement upon Hatcher's Run, on the 27th of October, it was again engaged, in which some prisoners were taken, but the enemy was found strongly posted. During the winter, the regiment remained in quarters with the corps. At the moment when the Union forces were about to move on the spring campaign, the rebel leader massed his troops, and before light on the morning of the 25th of March, made a sudden attack upon Fort Steadman, with the design of breaking the lines and destroying vast military stores at City Point. The fort was captured and considerable advantage gained, but was promptly met by forces of the Ninth Corps, and the effect of the blow inflicted quickly repaired. In this encounter the One Hundredth was engaged, and Lieutenant Coloiel Joseph H. Pentecost was killed. The final assault upon the city of Petersburg, on the 2d of April, closed the long list of engagements in which the regiment, during its four years of service, had participated. It soon after returned to City Point, and thence to Washington, where, on the 24th of July, it was mustered out of service.