Command in the South
By October 1780, the Continental Army had suffered several devastating defeats in the South under the command of Benjamin Lincoln and Horatio Gates, leaving the United States at a major disadvantage in the Southern theater of the war. On October 14, 1780, Washington, acting on the authorization of Congress, appointed Greene as the commander of the Southern Department of the Continental Army. By the time he took command, the British were in control of key portions of Georgia and South Carolina, and the governments of the Southern states were unable to provide much support to the Continental Army. Greene would face a 6,000-man British army led by General Cornwallis and cavalry commander Banastre Tarleton, as well as numerous Loyalist militias that worked with the British. Outnumbered and under-supplied, Greene settled on a strategy of guerrilla warfare rather than pitched battles in order to prevent the advance of the British into North Carolina and Virginia. His strategy would heavily depend on riverboats and cavalry to outmaneuver and harass British forces. Among Greene's key subordinates in the Southern campaign were his second-in-command, Friedrich Wilhelm von Steuben, cavalry commander Henry Lee, the Marquis de Lafayette, Daniel Morgan, and Francis Marion.
While en route to the Southern theater, Greene learned of the October 1780 American victory at the Battle of Kings Mountain, which postponed Cornwallis's planned advance into North Carolina. Upon arriving in Charlotte, North Carolina, in December 1780, Greene went against conventional military strategy by dividing his forces; he would lead the main American force southeast, while Morgan would lead a smaller detachment to the southwest. Cornwallis responded by dividing his own forces, marching the main detachment against Greene while Tarleton led a force against Morgan. In the January 1781 Battle of Cowpens, Morgan led Continental troops to a major victory that resulted in the near-total destruction of Tarleton's force. After the battle, Cornwallis set off in pursuit of Morgan, burning some of his own supplies in order to speed up his army's movement. Greene linked up with Morgan and retreated into North Carolina, purposely forcing Cornwallis away from British supply lines. On February 9, in consultation with Morgan and other top officers, Greene decided to continue the retreat north, heading toward the Dan River at the North Carolina-Virginia border.
With the British in close pursuit, Greene divided his forces, leading the main contingent north while sending a smaller group under Colonel Otho Williams to harass British forces. Greene's force outpaced the British and crossed the Dan River on February 14. Greene's contemporaries were impressed by the speed and efficiency of the retreat through difficult territory; Alexander Hamilton wrote that it was a "masterpiece of military skill and exertion." Unwilling to travel even farther from his supply lines, General Cornwallis led his army south to Hillsborough, North Carolina. On February 22, Greene's force crossed back over the Dan River to challenge Cornwallis in North Carolina.
After crossing back into North Carolina, Greene harassed Cornwallis's army. In early March, he received reinforcements from North Carolina and Virginia, doubling the size of his force to approximately 4,000 men. On March 14, he led his army to Guilford Courthouse and began preparing for an attack by Cornwallis, using a strategy based on Morgan's plan at the Battle of Cowpens. Greene established three defensive lines, with the North Carolina militia making up the first line, the Virginia militia making up the second line, and the Continental Army regulars, positioned on a hill behind a small stream, making up the third line. After skirmishes on the morning of March 15, the main British force launched a full attack in the afternoon, beginning the Battle of Guilford Court House. The first American line fired volleys and then fled, either to the next line or away from the battlefield. The second line held up for longer and continued to resist the British advance while Cornwallis ordered an unsuccessful assault against the third line. The British re-formed and launched an assault on the left flank of the third line, but were overwhelmed by Henry Lee's cavalry. In response, Cornwallis ordered his artillery to fire grapeshot into the fray, hitting British and American soldiers alike. With his army's left flank collapsing, Greene ordered a retreat, bringing the battle to an end. Although the Battle of Guilford Court House ended with an American defeat, the British suffered substantially greater losses.
After the Battle of Guilford Court House, Cornwallis's force headed south to Wilmington, North Carolina. Greene initially gave chase but declined to press for an attack after much of the militia returned home. To Greene's surprise, in late April Cornwallis's force began a march north to Yorktown, Virginia. Rather than follow Cornwallis, Greene headed South, where he challenged British commander Francis Rawdon for control of South Carolina and Georgia. On April 20, he began a siege of Camden, South Carolina, and established a camp at a nearby ridge known as Hobkirk's Hill. On the 25th, Rawdon launched a surprise attack on Greene's position, beginning the Battle of Hobkirk's Hill. Despite having been taken by surprise, Greene's force nearly achieved victory, but the left flank collapsed and the cavalry failed to arrive. Facing total defeat, Greene ordered a retreat, bringing an end to the battle. Although the American and British forces suffered a similar number of losses in the Battle of Hobkirk's Hill, Greene was deeply disappointed by the result of the battle.
On May 10, Rawdon's force left Camden for Charleston, South Carolina, effectively conceding control of much of interior South Carolina to the Continental Army. In a series of small actions, Greene and his subordinates further eroded British control of interior South Carolina by capturing several British forts. On June 18, after undertaking the month-long siege of Ninety Six, Greene launched an unsuccessful attack on the British fort at Ninety Six, South Carolina. Although the assault failed, Rawdon ordered the fort abandoned shortly thereafter. Meanwhile, Greene's subordinates further expanded Continental control, capturing Augusta, Georgia, on June 5. By the end of June, the British controlled little more than a thin strip of coastal land from Charleston to Savannah. After resting through much of July and August, the Continental Army resumed operations and engaged a British force on September 8 at the Battle of Eutaw Springs. The battle ended with a Continental retreat, but the British suffered more substantial losses. After the battle, the British force returned to Charleston, leaving interior South Carolina in full control of Continental forces. Congress issued Greene a gold medal and passed a resolution congratulating him for his victory at Eutaw Springs.
While Greene campaigned in South Carolina and Georgia, Lafayette led Continental resistance to Cornwallis's army in Virginia. Although Greene's command gave him leadership of Continental operations in Virginia, he was unable to closely control events in Virginia from South Carolina. Lafayette heeded Greene's advice to avoid combat, but his force only narrowly escaped destruction at the July 1781 Battle of Green Spring. In August, Washington and French general Rochambeau left New York for Yorktown, intent on inflicting a decisive defeat against Cornwallis. Washington laid siege to Cornwallis at Yorktown, and Cornwallis surrendered on October 19.
Yorktown was widely regarded as a disastrous defeat for the British, and many considered the war to have effectively ended in late 1781. The governments of North Carolina, South Carolina, and Georgia each voted Greene liberal grants of lands and money, including an estate called "Boone's Barony" in Bamberg County, South Carolina, and Mulberry Grove Plantation near Savannah. Nonetheless, the British still controlled New York, Savannah, and Charleston, and Greene still contended with Loyalist militias who sought to destabilize Continental control. With American finances in a disastrous state, Greene also struggled to clothe and feed his troops. In late 1781, he declined appointment to the newly created position of secretary of war, which was charged with overseeing the Continental Army. He also corresponded with Robert Morris, the superintendent of finance of the United States, who shared Greene's view on the need for a stronger national government than the one that had been established in the Articles of Confederation. No major military action occurred in 1782, and the British evacuated Savannah and Charleston before the end of that year. Congress officially declared the end of the war in April 1783, and Greene resigned his commission in late 1783.