October 12th, the day after Arnold was defeated at Valcour.  So far as its leading object went it was successful, Washington feeling obliged to let go the line of the Harlem, and change front to the left.  As the result of the various movements and encounters of the two armies, he fell back across the Hudson into New Jersey, ordering the evacuation of Fort Washington, and deciding to rest his control of the Hudson Valley upon West Point, fifty miles above New York, a position of peculiar natural strength, on the west bank of the river.  To these decisions he was compelled by his inferiority in numbers, and also by the very isolated and hazardous situation in which he was operating, between two navigable waters, absolutely controlled by the enemy’s shipping.  This conclusion was further forced upon him by another successful passage before the guns of Forts Washington and Lee by Hyde Parker, with three ships, on the 9th of October.  On this occasion the vessels, two of which were frigates of the heaviest class, suffered very severely, losing nine killed and eighteen wounded; but the menace to the communications of the Americans could not be disregarded, for their supplies came mostly from the west of the Hudson.

It was early in November that Washington crossed into New Jersey with five thousand men; and soon afterwards he directed the remainder of his force to follow.  At that moment the blunder of one subordinate, and the disobedience of another, brought upon him two serious blows.  Fort Washington not being evacuated when ordered, Howe carried it by storm, capturing not only it but its garrison of twenty-seven hundred men; a very heavy loss to the Americans.  On the other hand, the most explicit orders failed to bring the officer left in command on the east of the Hudson, General Charles Lee, to rejoin the commander-in-chief.  This criminal perverseness left Washington with only six thousand men in New Jersey, seven thousand being in New York.  Under these conditions nothing remained but to put the Delaware also between himself and the enemy.  He therefore retreated rapidly through New Jersey, and on the 8th of December crossed into Pennsylvania with an army reduced to three thousand by expiry of enlistments.  The detachment beyond the Hudson, diminishing daily by the same cause, gradually worked its way to him; its commander luckily being captured on the road.  At the time it joined, a few battalions also arrived from Ticonderoga, released by Carleton’s retirement to the foot of Champlain.  Washington’s force on the west bank of the Delaware was thus increased to six thousand men.