Fort Washington occupied a hilltop position some 230 feet above the Hudson River in northwestern Manhattan. Regarded by some as the “American Gibraltar," the fort and its sister installation, Fort Lee, offered the prospect of denying control of the Hudson to the vaunted British Navy. Fort Washington was unassailable from the west, but was less impressive from the other three directions. It was constructed as a five-sided earthen structure with several outlying redoubts, the most notable of which was Fort Tryon. Fort Washington was handicapped by its relatively small size and lack of an interior water supply.
During the construction of neighboring Fort Lee in the summer of 1776, General Israel Putnam suggested that old ships be sunk in the river in the vicinity of the forts to provide additional obstacles to the British Navy. That precaution was taken and it increased the belief of Nathanael Greene, commander of both forts, that his position was basically secure.
In the wake of the American defeat at White Plains in late October, Major General William Howe chose to forgo a direct assault against the Continental Army and instead turned his attention to Fort Washington.
In early November, William Demont, an American deserter, handed over drawings of the fort to British officers, enabling them to refine their attack plans for maximum effect. On November 5 three British ships sailed up the Hudson, slipped by the forts and avoided the sunken wrecks. The event deeply disturbed George Washington, who had harbored considerable misgivings about trying to hold Fort Washington. Washington’s suggestion that the fort be abandoned was rejected by the confident Greene, who left Colonel Robert Mcgaw of Pennsylvania in command of the installation, and joined the staff at headquarters in New Jersey.
On November 15, a British officer was sent to Fort Washington under a flag of truce. He demanded the facility's immediate surrender, then threatened that if his offer were refused, no quarter would be given to the defenders in the coming battle. Mcgaw declined the offer. On the following morning, British forces in the surrounding hills opened cannon fire on the fort and its outlying installations. Washington, Putnam and Greene crossed the Hudson from Fort Lee to examine conditions at Fort Washington, but concluded that they could not offer assistance and returned to New Jersey.
The British then launched a coordinated three-pronged attack and were met with initially stiff resistance. American soldiers at Fort Tryon, including Margaret Cochran Corbin, fought determinedly before falling back or being captured. So many soldiers from the outside positions sought refuge in Fort Washington that its effectiveness was impaired by overcrowding.
A vital contribution was made to the British cause by German forces under Colonel Johann Rall when they managed to scale the precipitous north wall of the fort. By mid-afternoon, it was evident to Colonel Mcgaw that the battle was lost and he accepted an offer to surrender. The threatened slaughter of the American defenders did not take place, a decision that was roundly criticized in some quarters. A number of British officers believed that had the soldiers in Fort Washington been massacred, then American resolve would have been weakened and the war would have come to a rapid end.
The British listed 67 killed, 335 wounded and six missing. The American lost 54 killed and more than 2,800 captured — a tremendous blow to the Patriot cause. Further, 43 cannon and various vital supplies ended up in British hands. Many captured American officers were later released, but the common soldiers were not so fortunate. Hundreds were incarcerated on unbelievably squalid British prison ships where they died in large numbers because of malnutrition and disease.
The loss of Fort Washington exerted a deep impact on the commander-in-chief. Washington regretted allowing Greene to have had the last word on the defense of the fort. In the future the general relied less on the suggestions of others and more on his own intuition.
Another result of the loss was the increasingly critical stance taken by Charles Lee. Never one to hide his light under a bushel, Lee corresponded directly with members of Congress, suggesting that the inept Washington be replaced and shamelessly offering himself as a replacement.
See also campaigns of 1776 and timeline of the War of Independence.