By the spring of 1781 and after six years of war, the British forces in America hung on to a handful of coastal bases surrounded by a largely hostile countryside. At the same time, they continued with what amounted to a global war against France and Spain. Back in England, the war was becoming both unpopular and divisive. The Yorktown Campaign ensured American efforts to win independence from Great Britain would end in success, and elevated General George Washington's notoriety as a result of his role directing the victory. Washington's Continental Army, substantially aided by French land and naval forces, surrounded the British southern army under the command of General Charles, Earl of Cornwallis. After a series of reverses and the depletion of his forces’ strength, the British commander in the southern colonies, General Lord Cornwallis, moved his army from Wilmington, North Carolina, eastward to Petersburg, Virginia, on the Atlantic coast, in May 1781. Cornwallis had about 7,500 men and was confronted in the region by only about 4,500 American troops under the marquis de Lafayette, General Anthony Wayne, and Frederick William, Freiherr (baron) von Steuben. The critical element for both options was French naval support. The Allies already had a smaller French fleet of twelve ships, carrying siege guns, at Newport, Rhode Island, but its commander, Admiral de Barras, was reluctant to go to the Chesapeake Bay and risk destruction along the way by British naval forces. Thanks to assiduous diplomatic efforts by American representatives in Paris, however, France provided more than troops and funds. They eventually consented to loaning the Americans the use of a much larger fleet during the Caribbean hurricane season–roughly from mid-July to mid-October.

The plan called for the larger French fleet, twenty-six ships under Admiral de Grasse, to provide local naval superiority (thereby, in modern terms, isolating the battlefield) so that the Allied army–American and French–could successfully attack a British force on land. Because Rochambeau could not tell Washington where the French fleet would go, nothing was decided in May, but the French Army was subsequently moved from Newport to join the Continental Army at Peekskill. The Yorktown Campaign of 1781, a decisive moment in the American Revolutionary War, saw a combined American and French force led by George Washington successfully besiege and force the surrender of British General Charles Cornwallis at Yorktown, Virginia, effectively ending major combat operations in the war and paving the way for American independence; this victory was largely due to a coordinated land and sea strategy that trapped the British army on a peninsula, leaving them with no escape route and ultimately forcing their surrender on October 19, 1781. American troops under Washington joined with a French fleet and land forces to surround Cornwallis' British army at Yorktown. Yorktown's peninsula geography made it difficult for the British to escape, allowing the allied forces to effectively trap them. The allied forces used artillery bombardments and trench warfare to gradually weaken the British defenses. Unable to withstand the siege, Cornwallis surrendered to Washington on October 19, 1781, marking a major turning point in the war.

While it took the Americans another two years of skillful diplomacy after Yorktown to win their independence in a formal peace treaty, the war was won with the British defeat at Yorktown. Through perseverance, skilled leadership from officers such as George Washington, and help from their French allies, the American Army won a great victory against the most powerful nation of that time period. Furthermore, the Yorktown Campaign demonstrated how much the American Army had improved in a relatively short period of time, in addition to providing an early successful example of the employment of joint and multinational forces. The negotiations for surrender were complicated by two issues. When American forces surrendered at Charleston in 1780, they were not granted customary terms of capitulation that included flying colors and the playing of an enemy tune. Washington insisted that these terms be applied to the surrender of the British army at Yorktown, his negotiators pointing out that the defenders had in both instances acted with valor. When the British garrison marched out of their positions on October 19 to surrender, it was with colors cased, and Cornwallis, claiming illness, did not attend the ceremony, sending his deputy General O'Hara to deliver his sword. The Yorktown campaign is considered a pivotal moment in American history, as the British surrender significantly boosted American morale and led to the start of peace negotiations that ultimately secured American independence.