New Windsor lies at the confluence of Chamber's creek with the Hudson, two miles south of Newburgh. Here, in a mansion of an humble Dutch style of architecture, Washington had his head-quarters; . . .It was for some time the headquarters of the Revolutionary army, and the stone house in which General Washington resided is still standing. While here in March, 1783, the famous Newburgh letters by an anonymous author, were published, for the purpose of exciting the army to revolt. The history of this affair, the noble conduct of Washington in reference to it, is described by Dunlap in his history of New York. They were afterwards ascertained to have been written by Major Armstrong, subsequently Secretary of War. The author, says Mr. Dunlap, assumes the character of a veteran, who had suffered with those he addressed. He tells them that to be tame in their present situation would be more than weakness, and must ruin them for ever. He bids them "suspect the man who would advise to more moderation and longer forbearance." He then describes the high state in which the country has been placed by their services, and says "does this country reward you with tears of gratitude and smiles of admiration, or does she trample upon your rights, disdain your cries, and insult your distresses!" He advised them to carry their appeal from the justice to the fears of government. " Assume a bolder tone- say, that the slightest indignity from Congress must now operate like the grave, and part you from them for ever. That if peace takes place, nothing shall separate you from your arms but death : if war continues, that you will retire to some unsettled country, with Washington at your head, and mock at the distresses of government. The insidious expression of "courting the auspices and inviting the direction of their illustrious leader, was calculated to make the army believe that Washington would join them in rebellion against his country, and was certainly a bold artifice, coming, as it did, from one in constant correspondence with Gen. Gates, and attached to him both by inclination and office."
The commander-in-chief noticed the anonymous address in orders, with pointed disapprobation, and requested that the general and field officers, with a proper representation from the staff of the army, would assemble on the 15th instant, to hear the report of the committee deputed by the army to Congress. This request was seized upon, and represented in a second paper as giving sanction to the proceedings of the officers, and they were called on to act with energy. On the 15th of March, General Washington addressed the convention of officers (General Gates being chairman) in the language of truth, feeling, and affection. He overthrew all the artifices of the anonymous writer and his friends, one of the principal of whom sat in the chair. Washington noticed the advice to mark for suspicion the man who should recommend moderation. He feelingly spoke of his own constant attention, from the commencement of the war, to the wants and sufferings of the army, and then pointed out the dreadful consequences of following the advice of the anonymous writer, either to draw their swords against their country or retire, if war continues, from the defence of all they hold dear. He calls to mind the scenes in which they had acted together, and pledges himself to the utmost exertion for obtaining justice to his fellows in arms. He requests them to rely on the promise of Congress. He said, " I conjure you, in the name of our common country, as you value your own sacred honour, as you respect the rights of humanity, to express your utmost horror and detestation of the man who wishes, under any specious pretences, to overturn the liberties of your country: and who wickedly attempts to open the flood-gates of civil discord, and deluge our rising empire in blood.
The convention resolved, unanimously, among other things, that, "the army have unshaken confidence in Congress, and view with abhorrence, and reject with disdain, the infamous propositions contained in a late anonymous address to the officers of the army."
In 1782 General Washington moved his headquarters to the home of John Hasbrouck in Newburgh. He remained there for the duration of the war. It was while he was stationed at Hasbrouck House that Washington made his famous refusal to be crowned king. The house became one of the first structures in America to be preserved because of its historical significance.
In 1883, the city of Newburgh, following suit with Philadelphia and the Centennial Exposition, held a great celebration to mark 100th anniversary of the disbanding of the Revolutionary army by General Washington at his headquarters in that city. Arthur G Adams in The Hudson Through the Years describes the festivities:
"At sunrise the celebration was ushered in by ringing of bells on all public buildings and the booming of cannons from Washington's headquarters, and from the seven ships composing the fleet of Rear-Admiral Cooper, which were drawn up in line in front of the city. At the same time there was an exhibit of Japanese day fire works.
At 9:00 AM the yards of the ships were manned, and at 10:00 AM a simultaneous landing was effected from every ship of the line. At 11:00 AM three guns, at intervals of twenty seconds, were fired from the flag-ship as a signal for the moving of the procession, .... A monument to Washington was dedicated before the afternoon ceremonies. ...In the evening there was an enormous display of fireworks from barges anchored in the Hudson, and also at Temple Hill in New Windsor and at Fishkill."