The New York and New Jersey campaign was a series of battles in the American Revolutionary War that took place from July 1776 to January 1777. The campaign was fought between the Continental Army under General George Washington and British forces under General Sir William Howe. The British were mostly victorious in the campaign. From the moment that Congress had named him commander of the newly formed Continental Army in the summer of 1775, George Washington had considered New York City and the valuable waterways it controlled as the key to an American victory. Confined entirely to the upper part of Manhattan Island, New York was the second largest city in the Thirteen Colonies, behind only Philadelphia, with a peacetime population of 20,000. Having withdrawn from Boston after an unsuccessful campaign, the British now focused on capturing New York City. General Sir William Howe, with the services of his brother, Admiral Lord Howe, began amassing troops on Staten Island in July 1776. General Washington, with a smaller army of about 19,000 men, was uncertain where the Howes intended to strike. In January 1776, Washington dispatched General Charles Lee to New York City to survey and plan for the city’s defense. Washington understood the importance of the Hudson River-Lake Champlain corridor to the American cause.

British possession of New York City, would threaten that vital line of communication between New England and the rest of the rebelling colonies. By mid-April, after Lee had worked with Washington to devise a multilayered plan in which troops would be stationed and ready to fight in different parts of the city, Continental soldiers began to leave New England for New York. In late August, the British transported about 22,000 men (including 9,000 Hessians) to Long Island. In the Battle of Long Island on August 27, 1776, the British outflanked the American positions, driving the Americans back to the Brooklyn Heights fortifications. General Howe then began to lay siege to the works, but Washington skillfully managed a nighttime retreat through his unguarded rear across the East River to Manhattan Island. On August 26 and 27, British forces followed a plan by General Henry Clinton in which the main portion of Howe’s force would march around the eastern flank of the American lines using roads the Americans had left unguarded. The results were catastrophic for the American forces whose defense rapidly evaporated in the face of the swiftly moving British forces. Within a matter of hours, the Americans had retreated to their defensive works on the Brooklyn heights.

During the Battle of Long Island, the British captured General John Sullivan. Admiral Howe convinced him to deliver a message to Congress in Philadelphia, and released him on parole. Washington also gave his permission, and on September 2 Sullivan told the Congress that the Howes wanted to negotiate, and had been given much broader powers to treat than those they actually held. General Howe, after consolidating British positions around New York harbor, detached 6,000 men under the command of two of his more difficult subordinates, Henry Clinton, and Hugh, Earl Percy to take Newport, Rhode Island and its strategic port east across Long Island Sound. The Americans withdrew across the Delaware River into Pennsylvania in early December. On January 3, Hugh Mercer, leading the American advance guard, encountered British soldiers from Princeton under the command of Charles Mawhood. The British troops engaged Mercer and in the ensuing battle, Mercer was mortally wounded. The British gained control of New York Harbor and the surrounding agricultural areas, and held New York City and Long Island until the war ended in 1783. The Americans suffered significant casualties and lost important supplies, but Washington managed to retain the core of his army and avoid a decisive confrontation that could have ended the war.