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. Cornwallis left Princeton with 8,000 men to attack Washington's army of 6,000 troops. Washington sent troops to skirmish with the approaching British to delay their advance. It was almost nightfall by the time the British reached Trenton. After three failed attempts to cross the bridge over the Assunpink Creek, beyond which were the primary American defenses, Cornwallis called off the attack until the next day.During the night, Washington called a council-of-war and asked his officers whether they should stand and fight, attempt to cross the river somewhere, or take the back roads to attack Princeton. Although the idea had already occurred to Washington, he learned from Arthur St. Clair and Cadwalader that his plan to attack Princeton was indeed possible. Two intelligence collection efforts, both of which came to fruition at the end of December 1776, supported such a surprise attack. After consulting with his officers, they agreed that the best option was to attack Princeton.

Mawhood ordered his light troops to delay Mercer, while he brought up the other detachments. Mercer was walking through William Clark's orchard when the British light troops appeared. The British light troops' volley went high, which gave time for Mercer to wheel his troops around into battle line. Mercer's troops advanced, pushing back the British light troops. Fifty light infantrymen were in pursuit of Mercer's men when a fresh brigade of 1,100 militiamen under the command of Cadwalader appeared. Mawhood gathered his men who were all over the battlefield and put them into battle line formation. Cadwalader was able to get one company to fire a volley but it fled immediately afterwards. At this point, Washington arrived with the Virginia Continentals and Edward Hand's riflemen. Washington ordered the riflemen and the Virginians to take up a position on the right hand side of the hill, and then Washington quickly rode over to Cadwalader's fleeing men. After entering Princeton, the Americans began to loot the abandoned British supply wagons and the town itself. With news that Cornwallis was approaching, Washington knew he had to leave Princeton. Washington wanted to push onto New Brunswick and capture a British pay chest of 70,000 pounds but Knox and Major General Nathanael Greene talked him out of it. Instead, Washington moved his army to Somerset Courthouse on the night of January 3, then marched to Pluckemin by January 5, and arrived at Morristown, by sunset the next day, for winter encampment. After the battle, Cornwallis abandoned many of his posts in New Jersey, and ordered his army to retreat to New Brunswick.