Washington’s fourth Westchester deployment, in July and August, 1781, brought the American and French Armies together for the first time. The Continental regiments, which had marched to Westchester from the Newburgh, New York, area, were deployed to the west of the Sprain Brook, on the hilltops of Dobbs Ferry and Ardsley. Most of the American Army was camped on the north side of today’s Heatherdell Road, in the area of Ardsley High School today. The French Army, which had marched to Westchester from Newport, across Rhode Island and Connecticut, was deployed to the east of the Sprain Brook, in Hartsdale and White Plains. Rochambeau’s headquarters, known as the Odell House, still stands on Ridge Road in Hartsdale. Washington’s headquarters were located at the Joseph Appleby House, just south of today’s Secor Road, near the Hartsdale-Ardsley border; the site is now the property of radio station WFAS.
The two armies remained encamped in those localities for six-and-a-half weeks. General Washington chose lower Westchester as the site of the allied encampment (traditionally known as the “Philipsburg Encampment”) because of its proximity to New York. (During the Revolutionary War, the Philipsburg Manor occupied a huge swath of territory along the Hudson River, extending from King’s Bridge in the south to the Croton River in the north. Most of the 1781 encampment was located within Philipsburg.) Washington hoped, with the help of the French, to gain a major victory by driving the British army from Manhattan.
If these were ambitious plans, it was out of necessity, for Washington knew that time was running out and that he had to deliver a knockout blow—for French assistance could not be continued indefinitely. Yes, France was making a major effort in 1781 by maintaining the army of Rochambeau in America. Moreover, France’s powerful West Indies fleet, under Admiral François-Joseph, comte de Grasse, had instructions to do duty in North American waters as well, in cooperation with Washington and Rochambeau.
But French expenditures in support of the American rebellion had been enormous. If the conflict could not be decided on the battlefield in 1781, Paris was determined to extricate itself and end the war in a different way, through a settlement mediated by the great European powers at a conference in Vienna.
Congress and General Washington understood that a Vienna settlement would apply the principle of uti possidetis (Latin for “as you possess it”). In a settlement under that principle, the opposing sides would take possession of the territories that their militaries claimed to control, and Virginia, the Carolinas, Georgia, and the vast territory between the Alleghenies and the Mississippi would almost certainly be retained by Great Britain. The truncated United States would be confined to a northeastern coastal strip. Moreover, the French would terminate their military support, and British armies would be poised to resume hostilities against the vulnerable republic at any time that seemed favorable to the Crown. Yet Congress, discouraged by the long, inconclusive war, instructed its representatives in Paris (John Adams and Benjamin Franklin) to accede to this plan.
A knockout blow would change everything. If the British were to suffer a major military defeat, such as the loss of New York, London would be forced to end the war on much more favorable grounds, making a conference in Vienna moot.
Over the month of July, Washington and Rochambeau probed for weaknesses in British defenses on Manhattan. But few weaknesses were found, and with each passing day, Washington had less and less reason to hope for a major victory at New York.
Then, on August 14, 1781, at the Westchester encampment, Washington received a correspondence from Admiral de Grasse, which caused him to alter his strategy. Historian Robert Leckie has called de Grasse’s communication “possibly the most momentous message of the entire war.” The admiral indicated that he was bringing his large fleet from the West Indies to the Chesapeake Bay, and that he would be ready to cooperate with Washington and Rochambeau in a joint land and sea campaign against General Cornwallis’ troops, who were then fortifying the hamlet of Yorktown in Virginia.
Upon receipt of de Grasse’s com-
munication, Washington weighed his options. Shifting operations to Virginia would entail huge risks and offered scant chance of success. On the other hand, if all went miraculously well, Cornwallis could be trapped, for he had placed himself in a dangerous position at Yorktown.
Washington decided to abandon plans to attack New York and to take the gamble of marching more than 400 miles from the Hudson to Virginia. “It was one of the great, dramatic moments of the Revolution,” says historian David Hackett Fischer in a 2009 interview: “If you think of the Revolution as a series of moments of contingency, in the sense of moments of choice—when they could have gone one way, or could have gone another—this was one of the great contingent moments in our history.”
Washington risked all on this march. Success would require almost perfect coordination of several armies and fleets at great distances. Success would also require the utmost secrecy, so that Cornwallis would not learn that Virginia was the destination of the allied armies until it was too late for him to escape from the trap.
Urgent preparations for the march were made from August 14 until August 18, and the allied armies broke camp on August 19, 1781; on that date, the American troops were assembled (“paraded for the march”) in Dobbs Ferry, east of the intersection of present-day Ashford Avenue and Broadway, before heading north along Broadway to the Hudson River crossing at King’s Ferry. The light infantry regiment, commanded by Col. Alexander Scammell, would most likely have been placed at the van of the American Army. (Read more about Scammell in the “Who’s Who” sidebar.)
The French Army departed the same day a few miles east of the Americans and followed a complicated series of byways to King’s Ferry along interior roads, including today’s Route 100 north to Pines Bridge, Route 118 in Yorktown Heights, and Route 202 west towards Peekskill, eventually ar-riving at Trolley Road and Kings Ferry Road in Montrose and Verplanck.
Remarkably, the major contingencies fell into place. The critical components of the operation, any one of which might easily have gone wrong and led to failure, all went right. And two months later to the day, on October 19, 1781, Cornwallis surrendered his army of 7,500 men to General Washington. Cornwallis’ defeat shocked London and proved to be the knockout blow that Washington needed. Five months after Yorktown, the faction in Parliament that favored the American war fell from power and was replaced by a government that was ready to accept an independent United States.
As a result of the Paris negotiations that followed, the United States won extremely favorable peace terms, largely due to skillful negotiating by the three American commissioners, John Adams of Massachusetts, Benjamin Franklin of Pennsylvania and John Jay of New York. Of the three, it was Jay who took the lead in ensuring that the Mississippi River would be recognized as the western boundary of the United States. The Paris negotiations led to the signing of the Treaty of Paris, which was ratified by Parliament and by Congress in 1783.