<P> The Battle of Long Island is also known as the Battle of Brooklyn and the Battle of Brooklyn Heights . It was fought on August 27, 1776 and was the first major battle of the American Revolutionary War to take place after the United States declared its independence on July 4, 1776 . It was a victory for the British Army and the beginning of a successful campaign that gave them control of the strategically important city of New York . In terms of troop deployment and fighting, it was the largest battle of the entire war . </P> <P> After defeating the British in the Siege of Boston on March 17, 1776, commander - in - chief General George Washington brought the Continental Army to defend the port city of New York, then limited to the southern end of Manhattan Island . Washington understood that the city's harbor would provide an excellent base for the British navy during the campaign, so he established defenses there and waited for the British to attack . In July, the British under the command of General William Howe landed a few miles across the harbor from Manhattan on the sparsely - populated Staten Island, where they were slowly reinforced by ships in Lower New York Bay during the next month and a half, bringing their total force to 32,000 troops . Washington knew the difficulty in holding the city with the British fleet in control of the entrance to the harbor at the Narrows, and he moved the bulk of his forces to Manhattan, believing that it would be the first target . </P> <P> On August 22, the British landed on the shores of Gravesend Bay in southwest Kings County, across the Narrows from Staten Island and more than a dozen miles south from the established East River crossings to Manhattan . After five days of waiting, the British attacked American defenses on the Guan Heights . Unknown to the Americans, however, Howe had brought his main army around their rear and attacked their flank soon after . The Americans panicked, resulting in twenty percent losses through casualties and captures, although a stand by 400 Maryland troops prevented a larger portion of the army from being lost . The remainder of the army retreated to the main defenses on Brooklyn Heights . The British dug in for a siege but, on the night of August 29--30, Washington evacuated the entire army to Manhattan without the loss of supplies or a single life . Washington and the Continental Army were driven out of New York entirely after several more defeats and forced to retreat through New Jersey and into Pennsylvania . </P> <P> In the first stage of the war, the British Army was trapped in the peninsular city of Boston and they abandoned it on March 17, sailing to Halifax, Nova Scotia to await reinforcements . Washington then began to transfer regiments to New York City which he believed the British would next attack because of its strategic importance . Washington left Boston on April 4, arrived at New York on April 13, and established headquarters at the former home of Archibald Kennedy on Broadway facing Bowling Green . Washington had sent his second in command Charles Lee ahead to New York the previous February to establish the city's defenses . </P>

What caused the american defeat in new york in 1776
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