After the successes at Boston, Washington knew that the British would put all their focus on New York. So Washington marched his men to New York for the summer. The Declaration of Indepedence was published on July 4.
Indeed the British sent 30,000 troops to New York in the summer of 1776, to quickly end the rebellion. The landing was massive; something like D-Day.
Consider this animated image of what happened after the landing. The Americans are blue; the British are red; the German Hessians are purple
At the end of the day, the Continental Army was cornered. Tens of thousands of the enemy were to the south and the East River was to the north. They didn't have enough boats or time to cross the river, and even if they did they would be easy targets during the crossing.
DECISION: You are Washington. What do you do?
Click here to see what happened?