Just a few weeks later in July 1776, British warships ran past the American gun positions on Manhattan and anchored in the Tappan Zee out of range of American land batteries. This threat triggered furious action in the Highlands and the Americans did everything possible to complete their forts on Popolopen Creek and to stretch a chain across the river between Fort Montgomery and Anthony's Nose on the east bank. [This first chain should not be confused with the second chain the Americans installed at West Point in 1778.]

Later, after the British defeated Washington on Long Island and at White Plains, the fortified positions in the Highlands assumed a critical importance to the American cause. Washington, after he visited the area in November, however, apparently thought that the Highland forts were strong enough to withstand a British advance and decided to move with his army toward New Jersey.

While some American soldiers completed the two forts at Popolopen Creek, others constructed Fort Independence overlooking Peekskill Bay, just south of Anthony's Nose. Simultaneously, engineers completed assembling an "iron chain" and moved it into place between Fort Montgomery and Anthony's Nose. Because of design and structural weaknesses, the chain broke, and the Patriots could not block the river in 1776. Farther north, other soldiers attempted to block the river between Plum Point (near modern Cornwall) and Pollepel Island (now Bannerman's Island) with underwater obstacles.

After facing several British threats in 1776, the soldiers in the Highlands settled down for the long, cold winter while Washington went south to fight his Christmas-New Year's campaign at Princeton and Trenton and to winter at Morristown, New jersey. Poised in a threatening position on the flank of the route between New York and Philadelphia, Washington's little army prevented Sir William Howe from moving between the cities and forced Howe to evacuate New Jersey. At the same time the Morristown camp and the Hudson defenses protected the only remaining land line of communications from Boston to Philadelphia, which ran down the valleys west of the Highlands. On the strength of those meager forces, buttressed by Patriot militia controlling the countryside, the Revolution survived its second winter.

More History of West Point

Introduction
1775: Constitution Island
1776: Twin Forts of the Popolopen
1777: Defeat in the Highlands
1778: Fortifications of West Point
1779: Stony Point
1780: Treason
1781-83: Yorktown to Peace
1802: US Military Academy