On October 6th, 300 Continental soldiers of the 5th New York regiment, 100 artillerymen of Lamb's Artillery, and some 300 Levies and militiamen defended the unfinished Fort Montgomery and Fort Clinton against a combined force of roughly 2,100 Loyalists, Hessians, and British regulars led by Lieutenant General Sir Henry Clinton attacked Forts Montgomery and Clinton from the landward side (which was only partially completed) with support from cannon fire from British ships on the Hudson River. The land columns attacking from west of the fort consisted of the New York Volunteers, the Loyal American Regiment, Emmerich's Chasseurs, the 57th and the 52nd Regiments of Foot.
The Americans had emplaced an iron chain and a boom across the Hudson River, protected by four warships, to impede the British flotilla.
"Lt. Col. Mungo Campbell and several British regulars approach the fort with a flag of truce indicating that they wish to avoid `further effusion of blood.' Clinton sends Lt. Col. William S. Livingston to meet the enemy. The British officer requests that the patriots surrender. They are promised that no harm would come to them. Livingston, in turn, invites Campbell to surrender and promises him and his men good treatment. Fuming at this audacity, the British resume the fight. British ships working against an ebb tide attack the forts and American vessels. A steady volley ensues with each side receiving a share of the bombardment. British officers Campbell and Vaughan close in on all sides of the twin forts. Leading his men into battle, Campbell is killed in a violent attack on the North Redoubt of Fort Montgomery. Vaughan's horse is shot from under him as he rides into battle at Fort Clinton.
After a fierce battle lasting until dark, the British pushed the courageous Americans from the forts at the points of their bayonets. The defenders are overpowered by sheer numbers and the British gain possession of Forts Montgomery and Clinton. American casualties numbered about 350 killed, wounded and captured, while the British paid a price of at least 190 killed and wounded. Those who were not killed or did not escape are shipped to the infamous Sugar House Prisons in New York City and then onto British "hell ships" (prison ships) in the harbor. A "return," or report of prisoners, is sent to communities in the Highlands to inform families of their loved ones' capture. It is up to the families to send provisions lest the prisoners starve. Countless patriots perish on the prison ships.
Forts Montgomery and Clinton, located just south of West Point, were built for the defense of the Hudson Highlands in 1776. It was here that British and loyalist troops overwhelmed Clinton's outnumbered patriots in October.
Although the Americans lost the battle for the Highlands, a relative handful of Americans aided in delaying British reinforcements from joining Burgoyne in the upper Hudson Valley and allowed Gates to gain much needed militia reinforcements in time to ultimately win Burgoyne's surrender at Saratoga.