Read stories about techniques used by General Washington and the Culper Spy Ring in the Revolutionary War.


Dead Drops

Dead drops are secret locations that allow two individuals to pass messages to one another. They were widely used during the American Revolution, often existing in remote locations so as to not draw the attention of the enemy. They are particularly effective because the agents involved never have to meet in-person.

The Culper Spy Ring utilized dead drops when the new information was ready to be transported. Robert Townsend, aka Samuel Culper Jr., utilized a dead drop when passing information through Setauket. A courier would leave Townsend’s information at a dead drop in a field owned by Abraham Woodhull, who would in turn pass the information along to Caleb Brewster via dead drop. This sophisticated system of espionage allowed the Culper Spy Ring to operate in secret through the entirety of the Revolutionary War.

Learn More about Espionage in the Revolutionary War

Chemical Reagents

Chemical reagents were used to reveal hidden messages embedded in innocent documents. A special invisible ink known as “Sympathetic ink” could disappear into paper initially, and then be revealed again after applying a chemical reagent. General Washington preferred this method of communication, as he was unable to meet openly with spies under his command.

At the beginning of the Revolutionary War, the British held an advantage in their invisible ink technology. George Washington commissioned James Jay, the brother of Founding Father John Jay, to create a new invisible ink that could be used by the Americans. Jay created and distributed the chemical reagent to Washington’s forces, which soon became known as “Sympathetic Stain”. James Jay’s innovation allowed secret messages to be placed in many forms of innocuous correspondence, and matched the British in that theater of espionage.

Identifying Marks and Clothes

The American Revolution was fought in the open, amongst the people. As such, spies often relied on their ability to blend into normal society in order to operate effectively. Subtle usage of identifying marks and clothing were used to signal fellow agents to one’s true allegiance.

Ann Bates, a British spy posing as a patriot, employed this tactic in 1778. Posing as a refugee, Bates was able to enter General Washington’s encampment at White Plains. She carried a small token that identified her as a British loyalist to an American officer who was also spying for the British. Because she was a woman, she was able to move freely through the camp, taking detailed notes of the military strength therein. The information she gathered was passed onto to British General Henry Clinton, who subsequently reinforced the British presence in Rhode Island. This ultimately resulted in French and American forces withdrawing from Newport.

Military Intelligence

Military intelligence was invaluable to General Washington during the Revolutionary War. Entire spy networks were created to intercept information pertaining to enemy troop movements, supply logistics, and officer’s correspondence, to name a few. Both information and counter-information were crucial in keeping the Americans one step ahead of the British.

A notable example of this occurred in 1775, prior to the British assault on Boston. General Washington discovered a gunpowder shortage in Cambridge, Massachusetts, which rendered the American force too weak to properly defend the region. Using a tactic of false information, Washington ordered all of the gunpowder barrels to be filled with sand and moved outside of Boston. This way, British spies would relay false military intelligence that the rebels were well supplied, making Washington’s position appear stronger than it was. The tactic succeeded, resulting in the British delaying their attack, and allowing Washington crucial time to resupply his troops.

Codes and Ciphers

Codes and ciphers allowed information to be masked by an elaborate system of substituted letters, numbers, and symbols. A piece of information would be written out in code, often appearing like gibberish to anyone except its intended recipient. This person possessed a key, or cipher, which translated the code so the true message would be understood.

Benjamin Tallmadge developed the Culper Code Book to encode and translate intelligence gathered by the Culper Spy Ring. This cipher substituted numbers, ranging from 1 to 764, for key words used in correspondence. For instance, 410 stood for “Fort” and 711 was code for “General Washington”. The Culper Code Book proved to be invaluable to the war effort, and was a major factor in the Culper Spy Ring remaining undetected for the duration of the Revolution.

Learn about the Culper Code Book


Couriers were invaluable to American spy networks during the Revolution. Their job was to transport information between agents within a spy ring. They would carry intelligence back and forth across enemy lines, a task that was extremely perilous. Couriers caught with intelligence faced execution by the British.

Austin Roe was the main courier for the Culper Spy Ring. He was a childhood friend of Abraham Woodhull, Benjamin Tallmadge, and sever other figures of the Culper Spy Ring. He became an active member of the ring in 1777, after which he would routinely carry American intelligence between Setauket and New York City, a journey of 55 miles one-way. Roe presented himself as a merchant, which helped justify his high volume of travel between British military centers. He was able to remain active and undetected for the duration of the revolution, later becoming known as the “Paul Revere of Long Island”.

Secret Signals

The Miriam and Ira D. Wallach Division of Art, Prints and Photographs: Picture Collection, The New York Public Library. "Elizabeth Zane at Fort Henry" The New York Public Library Digital Collections. 1850 - 1880.

The Miriam and Ira D. Wallach Division of Art, Prints and Photographs: Picture Collection, The New York Public Library. "Elizabeth Zane at Fort Henry" The New York Public Library Digital Collections. 1850 - 1880.

Secret signals were used throughout the American Revolution to aid communication among American spy networks. They were powerful tools in espionage, because they could be displayed in plain sight. Simple items could be set in specified patterns to alert fellow agents of new intelligence, to designate meeting apices, or convey to simple actions.

Anna Strong joined the Culper Spy Ring after her husband Selah Strong was imprisoned by the British under suspicion of espionage. Within the Culper Spy Ring, Anna Strong utilized secret signals to communicate to her fellow agent Caleb Brewster. She would hang a black petticoat on her clothesline, which sat on a high vantage point overlooking Long Island Sound. Brewster would discreetly enter the waterway, and would be directed to one of several dead drop locations that contained new intelligence to be transported to the American leadership.

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