The Battle of Trenton was a small but pivotal American Revolutionary War battle on the morning of December 26, 1776, in Trenton, New Jersey. After General George Washington's crossing of the Delaware River north of Trenton the previous night, Washington led the main body of the Continental Army against Hessian auxiliaries garrisoned at Trenton. After a brief battle, almost two-thirds of the Hessian force were captured, with negligible losses to the Americans. The battle significantly boosted the Continental Army's waning morale, and inspired re-enlistments.

The Continental Army had previously suffered several defeats in New York and had been forced to retreat through New Jersey to Pennsylvania. Morale in the army was low; to end the year on a positive note, George WashingtonCommander-in-Chief of the Continental Armydevised a plan to cross the Delaware River on the night of December 2526 and surround the Hessians' garrison.

Because the river was icy and the weather severe, the crossing proved dangerous. Two detachments were unable to cross the river, leaving Washington with only 2,400 men under his command in the assault, 3,000 fewer than planned. The army marched 9 mi (14.5 km) south to Trenton. The Hessians had lowered their guard, thinking they were safe from the Americans' army, and had no long-distance outposts or patrols. Washington's forces caught them off guard, and after a short but fierce resistance, most of the Hessians surrendered and were captured, with just over a third escaping across Assunpink Creek.

Despite the battle's small numbers, the victory inspired patriots and sympathizers of the newly formed United States. With the success of the ongoing revolution in doubt a week earlier, the army had seemed on the verge of collapse. The dramatic victory inspired soldiers to serve longer and attracted new recruits to the ranks.

The American Revolutionary War (April 19, 1775 – September 3, 1783), also known as the Revolutionary War or American War of Independence, secured a United States of America independent from Great Britain. Fighting began on April 19, 1775, followed by the Declaration of Independence on July 4, 1776. The American Patriots were supported by France and Spain, conflict taking place in North America, the Caribbean, and Atlantic Ocean. It ended on September 3, 1783 when Britain accepted American independence in the Treaty of Paris, while the Treaties of Versailles resolved separate conflicts with France and Spain.Established by Royal charter in the 17th and 18th centuries, the American colonies were largely autonomous in domestic affairs and commercially prosperous, trading with Britain and its Caribbean colonies, as well as other European powers via their Caribbean entrepôts. After British victory in the Seven Years' War in 1763, tensions arose over trade, colonial policy in the Northwest Territory and taxation measures, including the Stamp Act and Townshend Acts. Colonial opposition led to the 1770 Boston Massacre and 1773 Boston Tea Party, with Parliament responding by imposing the so-called Intolerable Acts.

On September 5, 1774, the First Continental Congress drafted a Petition to the King and organized a boycott of British goods. Despite attempts to achieve a peaceful solution, fighting began with the Battle of Lexington on April 19, 1775 and in June Congress authorized George Washington to create a Continental Army. Although the "coercion policy" advocated by the North ministry was opposed by a faction within Parliament, both sides increasingly viewed conflict as inevitable. The Olive Branch Petition sent by Congress to George III in July 1775 was rejected and in August Parliament declared the colonies to be in a state of rebellion.

Following the loss of Boston in March 1776, Sir William Howe, the new British commander-in-chief, launched the New York and New Jersey campaign. He captured New York City in November, before Washington won small but significant victories at Trenton and Princeton, which restored Patriot confidence. In summer 1777, Howe succeeded in taking Philadelphia, but in October a separate force under John Burgoyne was forced to surrender at Saratoga. This victory was crucial in convincing powers like France and Spain an independent United States was a viable entity.

France provided the US informal economic and military support from the beginning of the rebellion, and after Saratoga the two countries signed a commercial agreement and a Treaty of Alliance in February 1778. In return for a guarantee of independence, Congress joined France in its global war with Britain and agreed to defend the French West Indies. Spain also allied with France against Britain in the Treaty of Aranjuez (1779), though it did not formally ally with the Americans. Nevertheless, access to ports in Spanish Louisiana allowed the Patriots to import arms and supplies, while the Spanish Gulf Coast campaign deprived the Royal Navy of key bases in the south.

This undermined the 1778 strategy devised by Howe's replacement, Sir Henry Clinton, which took the war into the Southern United States. Despite some initial success, by September 1781 Cornwallis was besieged by a Franco-American force in Yorktown. After an attempt to resupply the garrison failed, Cornwallis surrendered in October, and although the British wars with France and Spain continued for another two years, this ended fighting in North America. In April 1782, the North ministry was replaced by a new British government which accepted American independence and began negotiating the Treaty of Paris, ratified on September 3, 1783.