The Battle of Princeton was a battle of the American Revolutionary War, fought near Princeton, New Jersey on January 3, 1777, and ending in a small victory for the Colonials. General Lord Cornwallis had left 1,400 British troops under the command of Lieutenant Colonel Charles Mawhood in Princeton. Following a surprise attack at Trenton early in the morning of December 26, 1776, General George Washington of the Continental Army decided to attack the British in New Jersey before entering the winter quarters.

On December 30, he crossed the Delaware River back into New Jersey. On the night of January 2, 1777, Washington repulsed a British attack at the Battle of the Assunpink Creek. That night, he evacuated his position, circled around General Cornwallis' army, and went to attack the British garrison at Princeton. On January 3, Brigadier General Hugh Mercer of the Continental Army clashed with two regiments under the command of Mawhood. Mercer and his troops were overrun, and Mercer was mortally wounded. Washington sent a brigade of militia under Brigadier General John Cadwalader to help them. The militia, on seeing the flight of Mercer's men, also began to flee. Washington rode up with reinforcements and rallied the fleeing militia. He then led the attack on Mawhood's troops, driving them back. Mawhood gave the order to retreat, and most of the troops tried to flee to Cornwallis in Trenton.

In Princeton, Brigadier General John Sullivan encouraged some British troops who had taken refuge in Nassau Hall to surrender, ending the battle. After the battle, Washington moved his army to Morristown, and with their third defeat in 10 days, the British evacuated Central Jersey. The battle was the last major action of Washington's winter New Jersey campaign.