After the victory at Long Island (August 1776), British troops under Richard Howe occupied New York City in September. American troops, commanded by George Washington, were forced to retreat to New Jersey. Despite the successes of Trenton (December 26, 1776) and Princeton (January 3, 1777), Philadelphia was occupied by British troops in the fall of 1777:Congress had to leave the city, along with 2/3 of the population. Washington was defeated in Pennsylvania (Battle of Brandywine; Battle of Germantown) and wintered at Valley Forge in dire conditions. However, after the Battle of Saratoga in New York State, British commander John Burgoyne had to surrender to Horatio Gates on October 17, 1777. This American victory encouraged France to enter the war on the side of the insurgents
Signing of the Treaty of Paris, 1783.
A treaty of alliance was signed on February 6, 1778 in Paris between France and the United States, thanks to the diplomatic action of Benjamin Franklin. The French hoped to take their revenge on Great Britain. Spain joined the alliance in May 1779, followed by the United Provinces in 1780.
On June 18, 1778, British troops evacuated Philadelphia to concentrate on the defense of New York, threatened by French maritime intervention. The Battle of Monmouth (New Jersey, June 28, 1778) was an American success. But from 1779, the British attacked the Southern States:Savannah (Georgia) was occupied; the siege of the city organized by the Franco-Americans failed on October 9, 1779. Between May 1780 and September 1781, a series of battles took place in South Carolina which were sometimes favorable to the British (capture of Charleston on May 12, 1780; Camden , August 16, 1780), sometimes favorable to the Americans (Battle of King's Mountain, October 7, 1780; Eutaw Springs, September 9, 1781). The British defeat at Yorktown in Virginia (October 1781) marked a turning point in the war. The House of Commons voted to end the war on February 27, 1782, and British Prime Minister Lord North resigned on March 20. Savannah was evacuated by British troops on July 11, 1782, Charleston on December 14. Negotiations began with Great Britain and a preliminary treaty was concluded on November 30, 1782. The Treaty of Paris signed on September 3, 1783 officially put an end to hostilities and sanctioned the official recognition of the United States, whose border was to the Mississippi River. The Treaty of Versailles settled disputes between Britain and America's European allies.