The Battle of the Assunpink Creek, also known as the Second Battle of Trenton, was a battle between American and British troops that took place in and around Trenton, New Jersey, on January 2, 1777, during the American Revolutionary War, and resulted in an American victory. Following the victory at the Battle of Trenton early in the morning of December 26, 1776, General George Washington of the Continental Army and his council of war expected a strong British counterattack. Washington and the council decided to meet this attack in Trenton and established a defensive position south of the Assunpink Creek. On January 1, money from the Continental Congress arrived in Trenton and the men were paid. Washington also received a series of resolves from Congress including one that gave Washington powers similar to those of a military dictator. Washington decided that he would stand and fight at Trenton, and ordered General John Cadwalader, who was at Crosswicks with 1,800 militia, to join him in Trenton. On December 31, Washington learned that an army of 8,000 men under the command of Cornwallis was moving to attack him at Trenton. Washington ordered his men to build earthworks that were parallel to the south bank of the Assunpink Creek southeast of Trenton proper. Washington could not escape across the Delaware because all of his boats were a few miles upstream. Washington told his officers that he planned to move the army and that their current position was only temporary.

Out in front of his army, Cornwallis placed a skirmish line of Hessian jägers and British light infantry. Two days before, Washington had troops under the command of Matthias Alexis Roche de Fermoy place an outer defensive line halfway between Trenton and Princeton to delay the British advance. As the British approached, Fermoy returned to Trenton, drunk. Colonel Edward Hand took over his command. As the British came within range, the American riflemen opened fire. The American riflemen took cover in the woods, ravines, and even in bends in the road, and each time the British would line up in a battle line, the riflemen would fall back and fire from cover. As the British prepared to attack the American defenses, cannon, and musket fire were exchanged between the opposing sides. When Cornwallis arrived in Trenton with the main army, he called a council of war to determine whether he should continue to attack. During the night, the American artillery, under the command of Henry Knox, occasionally fired shells into Trenton to keep the British on edge. As Cornwallis had, Washington also called for a council of war. He would take the little-known Quaker road leading to Princeton, and his council of war agreed to attack the British garrison there. By 2 am on January 3, the army was on its way to Princeton. British forces perceived the movement, but Cornwallis believed this to be Americans planning a night attack and ordered British troops into defensive positions. This allowed the Americans to successfully march their army around Cornwallis.