The Battle of Forts Clinton and Montgomery was an American Revolutionary War battle fought in the Hudson Highlands of the Hudson River valley, not far from West Point, on October 6, 1777. British forces under the command of General Sir Henry Clinton captured Fort Clinton and Fort Montgomery and then dismantled the first iteration of the Hudson River Chains. The purpose of the attack was to create a diversion to draw American troops from the army of General Horatio Gates, whose army was opposing British General John Burgoyne's attempt to gain control of the Hudson. The highland region of the Hudson River valley (near West Point) was defended by Continental Army troops and state militia under the command of Putnam, who was based at Peekskill. Several miles upriver from Peekskill, just above the Popolopen Gorge where Popolopen Creek enters the Hudson, the Americans had placed a chain across the Hudson River to prevent British naval vessels from sailing further upriver. The chain's western end was guarded by Fort Montgomery, which also overlooked the gorge to the south. Also, on the west side of the river, south of the gorge, they had established Fort Clinton. Fort Montgomery, which was still undergoing construction, was under the command of George Clinton, while Fort Clinton was under the command of James Clinton. The detachment from Fort Montgomery numbered about 100 men and included a small artillery piece commanded by Captain John Lamb. Setting up a defensive position about one mile from the fort, they engaged Campbell's tired forces with spirit. While they were eventually forced to retreat, they were able to spike the field piece before abandoning it to the British.

After another stand closer to the fort, supported by 12-pound piece, they again retreated. The main approach to Fort Clinton was via a narrow strip of land about 400 yards wide between a small lake and the river. In addition to being covered by the fort's cannons, Governor Clinton had protected the approach by placing abatis to impede the British advance. Sir Henry sent the 63rd Foot around the lake to attack the fort from the northwest. At the same time, he first sent the light companies of the 7th and 26th regiments and a company of Anspach grenadiers against the main works, followed by the 26th Foot and a detachment from the 17th Light Dragoons, and then the remaining British and German companies. As at Fort Montgomery, the defenders were eventually overwhelmed. Those who surrendered, however, were not subjected to the savagery that took place to the north. A number of the garrison, including General Clinton, escaped by scrambling down the embankment to the river, where gunboats took them to safety across the river. The Americans were also forced to destroy a number of boats in the area, as unfavorable winds prevented them from escaping upriver. The next day, Henry Clinton sent a small detachment to Fort Constitution, a small outpost opposite West Point, and demanded its surrender. The lightly manned garrison at first refused, but it retreated on October 8 in the face of a larger attack force. George Clinton and Putnam strategized on their next move. Clinton opted to move north with troops on the western shore, as a defense against attacks further upriver, while Putnam would take steps to defend against attacks to the east. Captain James Wallace had begun clearing the river of American-laid obstacles following the battle.