The force which had so ably defended Savannah remained there in quarters during the winter of 1779 and 1780. In the month of March 1780, Sir Henry Clinton arrived before Charleston with a force from New York, which he immediately invested and rigorously pushed the siege. The chief engineer, Captain Moncrieff was indefatigable, and being fearless of danger, was careless of the lives of others. Having served two years with the 71st, and believing it would gratify the Highlanders to select them for dangerous service, he generally applied for a party of that corps for all exposed duties.

After the surrender of Charleston, on May 12, 1780, to the army under Sir Henry Clinton, the British forces in the southern states were placed under the command of lord Cornwallis. The 71st composed a part of this army, and with it advanced into the interior. In the beginning of June, the army amounting to twenty-five hundred, reached Camden, a central place fixed upon for headquarters. The American general, Horatio Gates, having, in July, assembled a force marched towards Camden. The people generally were in arms and the British officers perplexed. Major Macarthur who was at Cheraw to encourage the royalists, was ordered to fall back towards Camden. Lord Cornwallis, seeing the gathering storm hastily left Charleston and joined lord Rawdon at Camden, arriving there on August 13th. Both generals of the opposing forces on the night of August 15th moved towards each other with the design of making an attack. The British troops consisted of the 23d and 33d regiments, under Lieutenant-Colonel Webster; Tarleton's legion; Irish volunteers; a part of Lieutenant-Colonel Hamilton's North Carolina Regiment; Bryan's corps of royalists, under lord Rawdon, with two six and two three pounders commanded by Lieutenant McLeod; and the 71st regiment. Camden was left in the care of Major Macarthur, with the sick and convalescents.

Both armies were surprised, and each fired at the same moment, which occurred at three o'clock on the morning of August 16th. Both generals, ignorant of each other's force, declined general action, and lay on their arms till morning. When the British army formed in line of battle, the light infantry of the Highlanders, and the Welsh fusileers were on the right; the 33d regiment and the Irish volunteers occupied the center; the provincials were on the left, with the marshy ground in their front. While the army was thus forming, Captain Charles Campbell, who commanded the Highland light companies on the right, placed himself on the stump of an old tree to reconnoitre, and observing the Americans moving as with the intention of turning his flank, leaped down, and giving vent to an oath, called to his men, "Remember you are light infantry; remember you are Highlanders: Charge!" The attack was rapid and irresistible, and being made before the Americans had completed their movement by which they were to surround the British right, they were broken and driven from the field, prior to the beginning of the battle in other parts of the line. When the battle did commence the American center gained ground. Lord Cornwallis opened his center to the right and left, till a considerable space intervened, and then directed the Highlanders to move forward and occupy the vacant space. When this was done, he cried out, "My brave Highlanders, now is your time." They instantly rushed forward accompanied by the Irish volunteers and the 33d, and penetrated and completely overthrew the American column. However the American right continued to advance and gained the ground on which the Highlanders had been placed originally as a reserve. They gave three cheers for victory; but the smoke clearing up they saw their mistake. A party of Highlanders turning upon them, the greater part threw down their arms, while the remainder fled in all directions. The victory was complete. The loss of the British was one captain, one subaltern, two sergeants, and sixty-four soldiers killed; and two field officers, three captains, twelve subalterns, thirteen sergeants, and two hundred and thirteen soldiers wounded. The Highlanders lost Lieutenant Archibald Campbell and eight soldiers killed; and Captain Hugh Campbell, Lieutenant John Grant, two sergeants, and thirty privates wounded. The loss of the Americans was never ascertained, but estimated at seven hundred and thirty two.

General Sumter, with a strong corps, occupied positions on the Catawba river, which commanded the road to Charleston, and from which lord Cornwallis found it necessary to dislodge him. For this purpose Colonel Tarleton was sent with the cavalry and a corps of light infantry, under Captain Charles Campbell of the 71st regiment. The heat was excessive; many of the horses failed on the march, and not more than forty of the infantry were together in front, when, on the morning of the 18th, they came in sight of Fishing Creek, and on their right saw the smoke at a short distance. The sergeant of the advanced guard halted his party and then proceeded to ascertain the cause of the smoke. He saw the encampment, with arms piled, but a few sentinels and no pickets. He returned and reported the same to Captain Campbell who commanded in front. With his usual promptness Captain Campbell formed as many of the cavalry as had come up, and with the party of Highland infantry, rushed forward, and directing their route to the piled arms, quickly secured them and surprised the camp. The success was complete; a few were killed; nearly five hundred taken prisoners, and the rest dispersed. But the victory was dampened by the loss of the gallant Captain Campbell, who was killed by a random shot.

These partial successes were soon counterbalanced by defeats of greater importance. From what had been of great discouragement, the Americans soon rallied, and threatened the frontiers of South Carolina, and on October 7th overthrew Major Ferguson at King's Mountain, who sustained a total loss of eleven hundred and five men, out of eleven hundred and twenty-five. At the plantation of Blackstocks, November 20th, Colonel Tarleton, with four hundred of his command, engaged General Sumter, when the former was driven off with a loss of ninety killed, and about one hundred wounded. The culminating point of these reverses was the battle of the Cowpens.

A new commander for the southern department took charge of the American forces, in the person of Major-General Nathaniel Greene, who stood, in military genius, second only to Washington, and who was thoroughly imbued with the principles practiced by that great man. Lord Cornwallis, the ablest of the British tacticians engaged in the American Revolution, found more than his equal in General Greene. He had been appointed to the command of the Southern Department, by Washington, on October 30, 1780, and immediately proceeded to the field of labor, and on December 3rd, took formal command of the army, and was exceedingly active in the arrangement of the army, and in wisely directing its movements. His first arrangement was to divide his army into two detachments, the larger of which, under himself was to be stationed opposite Cheraw Hill, on the east side of the Pedee river, about seventy miles to the right of the British army, then at Winnsborough. The other, composed of about one thousand troops, under General Daniel Morgan, was placed some fifty miles to the left, near the junction of Broad and Parcolet rivers. Colonel Tarleton was detached to disperse the little army of General Morgan, having with him, the 7th or Fusileers, the 1st battalion of Fraser's Highlanders, or 71st, two hundred in number, a detachment of the British Legion, and three hundred cavalry. Intelligence was received, on the morning of January 17, 1781, that General Morgan was drawn up in front on rising ground. The British were hastily formed, with the Fusileers, the Legion, and the light infantry in front, and the Highlanders and cavalry forming the reserve. As soon as formed the line was ordered to advance rapidly. Exhausted by running, it received the American fire at the distance of thirty or forty paces. The effect was so great as to produce something of a recoil. The fire was returned; and the light infantry made two attempts to charge, but were repulsed with loss. The Highlanders next were ordered up, and rapidly advancing in charge, the American front line gave way and retreated through an open space in the second line. This manœuvre was made without interfering with the ranks of those who were now to oppose the Highlanders, who ran in to take advantage of what appeared to them to be a confusion of the Americans. The second line threw in a fire upon the 71st, when within forty yards which was so destructive that nearly one half their number fell; and those who remained were so scattered, having run a space of five hundred yards at full speed, that they could not be united to form a charge with the bayonet. They did not immediately fall back, but engaged in some irregular firing, when the American line pushed forward to the right flank of the Highlanders, who now realized that there was no prospect of support, and while their number was diminishing that of their foe was increasing. They first wavered, then began to retire, and finally to run. This is said to have been the first instance of a Highland regiment running from an enemy.[170] This repulse struck a panic into those whom they left in the rear, and who fled in the greatest confusion. Order and command were lost, and the rout became general. Few of the infantry escaped, and the cavalry saved itself by putting their horses to full speed. The Highlanders reformed in the rear, and might have made a soldier-like retreat if they had been supported.

The battle of the Cowpens was disastrous in its consequences to the British interests, as it inspired the Americans with confidence. Colonel Tarleton had been connected with frequent victories, and his name was associated with that of terror. He was able on a quick dash, but by no means competent to cope with the solid judgment and long experience of General Morgan. The disposition of the men under General Morgan was judicious; and the conduct of Colonels Washington and Howard, in wheeling and manœuvering their corps, and throwing in such destructive volleys on the Highlanders, would have done credit to any commander. To the Highlanders the defeat was particularly unfortunate. Their officers were perfectly satisfied with the conduct of their men, and imputing the disaster altogether to the bad dispositions of Colonel Tarleton, made representations to lord Cornwallis, not to be employed again under the same officer, a request with which compliance was made. This may be the reason that Colonel Tarleton gives them no credit in his "History of the Campaigns," published in 1787. He admits his loss to have been three hundred killed and wounded and near four hundred prisoners.[171]

After the battle of the Cowpens lord Cornwallis with increased exertions followed the main body of the Americans under General Greene, who retreated northward. The army was stripped of all superfluous baggage. The two battalions of the 71st now greatly reduced, were consolidated into one, and formed in a brigade with the 33d and Welsh Fusileers. Much skirmishing took place on the march, when, on March 16th, General Greene believing his army sufficiently strong to withstand the shock of battle drew up his force at Guilford Court House, in three lines.

The British line was formed of the German regiment of De Bos, the Highlanders, and guards, under General Leslie, on the right; and the Welsh Fusileers, 33d regiment, and second battalion of guards, under General Charles O'Hara, on the left; the cavalry was in the rear supported by the light infantry of the guards and the German Yagers. At one o'clock the battle opened. The Americans, covered by a fence in their front, maintained their position with confidence, and withheld their fire till the British line was within forty paces, when a destructive fire was poured into Colonel Webster's brigade, killing and wounding nearly one-third. The brigade returned the fire, and rushed forward, when the Americans retreated on the second line. The regiment of De Bos and the 33d met with a more determined resistance, having retreated and advanced repeatedly before they succeeded in driving the Americans from the field. In the meantime, a party of the guards pressed on with eagerness, but were charged on their right flank by a body of cavalry which broke their line. The retreating Americans seeing the effect of this charge, turned and recommenced firing. The Highlanders, who had now pushed round the flank, appeared on a rising ground in rear of the left of the enemy, and, rushing forward with shouts, made such an impression on the Americans, that they immediately fled, abandoning their guns and ammunition.

This battle, although nominally a victory for the British commander, was highly beneficial to the patriots. Both armies displayed consummate skill. Lord Cornwallis on the 19th decamped, leaving behind him between seventy and eighty of his wounded soldiers, and all the American prisoners who were wounded, and left the country to the mercy of his enemy. The total loss of the British was ninety-three killed, and four hundred and eleven wounded. The Highlanders lost Ensign Grant, and eleven soldiers killed, and four sergeants and forty-six soldiers wounded. It was long a tradition, in the neighborhood, that many of the Highlanders, who were in the van, fell near the fence, from behind which the North Carolinians rose and fired.