What was the first major American victory in the Revolutionary War?

The Battle of Saratoga on October 7, 1777 resulted in the first major American victory of the Revolutionary War. General Horatio Gates and General Benedict Arnold defeated English General Burgoyne. The British army received over 600 British casualties. The American losses were about 150 men.

So, on October 17, 1777 General Burgoyne and his entire army of 5700 men surrender to the Americans led by General Gates. The British were then marched to Boston, placed on ships; and, sent back to England after swearing not serve again in the war against America. The American Revolution, which had begun as a civil conflict between Britain and its colonies, had now become a world war.

The Battle of Saratoga was the turning point of the war. Revolutionary confidence and determination was renewed. What was more important, the victory encouraged France to make an open alliance with the Americans, after two years of semi-secret support. For the British government, the war had become much more complicated.

The American Congress declared December 18, 1777 as a national day "for solemn Thanksgiving and praise" in recognition of the military success at Saratoga; it is considered the nation's first official observance of a holiday using the actual name Thanksgiving.