This movement was decided upon by Washington and his generals at a council of war; the garrison was withdrawn from Governor's Island, and after the surplus ammunition and military stores had been forwarded to a point of safety, the troops leisurely followed after toward the north.

Putnam, Heath, and Spencer were placed in command of the three grand divisions into which the army was divided preparatory for retreat and stationed along the East River, Putnam, as usual, having the most perilous situation, at the lower end of the city.

To him was committed the removal of the troops and military stores, so that he had no more time at command than formerly.
Yet the British did not move upon the city with precipitation.
Commander-in-Chief Howe had learned his lesson by heart at Bunker Hill, and was no longer in haste to attack his brave opponents unless with overwhelming numbers, whether entrenched or otherwise.

He had resolved upon a series of flank movements, for the purpose of cutting off the American retreat northward, and on the 15th of September put the first in execution.

Washington was at his new headquarters, the Jumel mansion, at Harlem Heights, and Old Put was busy hurrying off the last of the detachments down in the city, when both heard the booming of cannon at Kip's Bay.