Washington relied on many people for intelligence during the Revolutionary War, ranging from unknown persons, often barely literate and of apparent low status, to low-ranking Continental and militia officers to members of the Continental Congress and other prominent citizens of the various states in which the war was waged. One of the persons from the latter category who took in interest in assisting Washington’s efforts to gather intelligence was William Duer of New York, who opened correspondence on the subject with Washington after the Continental army set up headquarters at Morristown, New Jersey, in early 1777.
William Duer (1747-1799), a member of the New York convention from Charlotte County, took an active part in efforts to obstruct and defend the Hudson River beginning in July 1776. Born in England, Duer served briefly during his teens as an aide-de-camp to Lord Clive in India and subsequently went to the West Indies where he had inherited property from his father. In 1768 Duer, having obtained a contract to supply spars and masts to the Royal Navy, visited New York in search of timber land, and on the advice of Philip Schuyler, he purchased a large tract at Fort Miller a short distance north of Saratoga. Duer settled permanently in the colony about 1773, and although he declined appointment as Continental deputy adjutant general for New York in August 1775 to avoid jeopardizing his family’s interests in the West Indies, he soon proved himself to be an energetic and useful supporter of the American cause. In September 1776 the New York convention named Duer to the colony’s committee of safety and the committee for detecting conspiracies, and in March 1777 it elected him a delegate to the Continental Congress. Duer attended Congress from April 1777 to November 1778 and served on the Board of War for most of that time. He subsequently furnished some supplies to the French army, and in 1782 he secured a contract for supplying the Continental forces in New York and New Jersey. The great financial empire that Duer created after the war, based on western land spectulation and banking schemes, collapsed in 1792. 
Biographical information on William Duer
- Born in Devonshire, England, 18 March 1743
- Completed preparatory studies and attended Eton College (England)
- 1765 became aide-de-camp to Lord Clive, Governor General of the East India Company
- Immigrated to America in 1768 and settled in Fort Miller, N.Y.
- Appointed justice of the peace on July 1, 1773
- First judge of Charlotte (now Washington) County
- Built the first saw and grist mills at Fort Miller, and later erected a snuff mill and a powder mill
- Prominent in the Revolutionary movement
- Member of the Provincial Congress in 1776 and 1777
- Served in the State senate in 1777
- Appointed judge of the court of common pleas in 1777 and reappointed in 1778
- Moved to Fishkill, N.Y., and later to what is now Paterson, N.J., where he erected the first cotton mill
- Member of the Continental Congress in 1777 and 1778
- Moved to New York City in 1783
- Served as a member of the State assembly in 1786
- Assistant to the Secretary of the Treasury Department 1789-1790
- Died in New York City April 18, 1799 while on parole from debtor’s prison
- Interment in the family vault under the old church of St. Thomas; reinterment in Jamaica, Long Island, N.Y. 
1. From Philander D. Chase, ed., The Papers of George Washington, Revolutionary War Series, vol. 5, June – August 1776 (Charlottesville and London: University Press of Virginia, 1993), 238-39.
2. Information obtained from Biographical Directory for the U.S. Congress, 1774 – present and Robert F. Jones “The king of the Alley” William Duer: Politician, Entrepreneur, and Speculator, 1768-1799 (Philadelphia: American Philosophical Society, 1992).