Long Island was occupied by British forces for most of the Revolutionary War, but that also made it one of George Washington’s most valuable sources of intelligence.
Beginning in 1778, a secret network centered largely around Setauket carried information from British-controlled New York City across Long Island, over Long Island Sound and eventually to Washington’s headquarters. The group became known as the Culper Spy Ring, and its members included a farmer, a tavern keeper, a merchant, a whaleboat captain and several other Long Islanders who operated at considerable risk.
They used aliases, numerical codes, invisible ink and carefully arranged courier routes to report on British troops, ships and military plans.
More than two centuries later, many of the places connected to the Culper Spy Ring are still standing on Long Island.
What was the Culper Spy Ring?
The Culper Spy Ring was an American intelligence network created during the Revolutionary War to gather information from British-occupied New York and Long Island for General George Washington.
By 1778, New York City had been under British control for two years and served as the headquarters of British military operations in North America.
Washington needed dependable information from behind British lines.
Major Benjamin Tallmadge, a Continental Army officer who had grown up in Setauket, became the central military organizer of the network. He relied heavily on people he knew from his Long Island hometown, including Abraham Woodhull and Caleb Brewster.
The network operated for about five years and became one of Washington’s most successful intelligence operations.
Nathan Hale showed Washington the danger of Revolutionary War spying
Washington had tried gathering intelligence in New York before the Culper network existed.
One of the best-known early attempts involved Nathan Hale, the young Continental Army officer and former schoolteacher who entered British-controlled territory to gather information in 1776.
Hale was captured and hanged by the British in Manhattan in September 1776. He is traditionally credited with declaring before his execution, “I only regret that I have but one life to lose for my country.”
His failed solo mission demonstrated one of the fundamental problems with early American intelligence gathering: sending a single inexperienced officer behind enemy lines was extraordinarily dangerous.
Washington experimented with other intelligence operations before the network that became known as the Culper Spy Ring emerged in 1778.
Why was it called the Culper Spy Ring?
The network was not publicly known as the Culper Spy Ring while its members were operating.
Abraham Woodhull used the alias “Samuel Culper,” later becoming “Samuel Culper Sr.” after another spy began using “Samuel Culper Jr.”
The origin of the Culper name has traditionally been linked to Culpeper County, Virginia, where George Washington had worked as a young surveyor. Washington is often credited with suggesting the name, although historians do not have a definitive account of exactly how it was chosen.
Whatever its origin, the Culper name eventually became attached to the entire intelligence network.
Setauket became the center of George Washington’s Long Island spy network
Setauket was particularly useful because Benjamin Tallmadge knew the community and could recruit people he trusted.
Abraham Woodhull, a Setauket farmer and Tallmadge’s friend and neighbor, became the central organizer of the operation on Long Island.
Woodhull initially traveled into New York City himself, observing British activity and gathering information. The trips were dangerous. British and Loyalist troops controlled Long Island, and travelers could be questioned, searched or detained.
As the operation developed, Woodhull increasingly coordinated intelligence from Setauket rather than making repeated journeys into Manhattan.
He survived the war and is buried in the cemetery at Setauket Presbyterian Church, where his grave recognizes his Revolutionary War service.
How did the Culper Spy Ring get messages to George Washington?
The route used by the Culper network was one of the most impressive parts of the operation.
Information gathered in British-controlled New York City could travel roughly like this:
- Robert Townsend collected intelligence in Manhattan.
- Couriers carried reports across the East River and approximately 55 miles east through British-controlled Long Island.
- The messages reached Abraham Woodhull in Setauket.
- Caleb Brewster transported them by whaleboat across Long Island Sound to Connecticut.
- Benjamin Tallmadge and military couriers carried the intelligence toward Washington’s headquarters.
Setauket’s location along Long Island Sound was essential to the system.
The waterways and secluded coves along the North Shore allowed Brewster and his crews to move between Long Island and Connecticut, although those crossings were far from routine. British vessels and Loyalist forces operated throughout the area.
Who was Abraham Woodhull?
Abraham Woodhull was one of the most important members of the Culper Spy Ring.
The Setauket farmer used the alias Samuel Culper and coordinated much of the network’s activity on Long Island.
Early in the operation, Woodhull personally traveled between Setauket and New York City to gather intelligence. Those journeys increasingly worried him as British suspicions grew.
His concerns were justified.
In 1779, a man named John Wolsey gave information about Woodhull to Lt. Col. John Graves Simcoe, commander of the Queen’s Rangers. Simcoe traveled to Setauket looking for Woodhull, but the spy happened to be in New York at the time.
Simcoe’s men instead attacked and plundered Woodhull’s father.
Woodhull later expressed his anger in a letter, writing that if he were somewhere without fear of “Law or Gospel,” he would kill Simcoe “for his usage to me.”
The incident helped demonstrate why Woodhull needed someone else to handle intelligence gathering in Manhattan.
Who was Robert Townsend, or Samuel Culper Jr.?
In 1779, Woodhull recruited Oyster Bay merchant Robert Townsend to gather intelligence in New York City.
Townsend became “Samuel Culper Jr.,” while Woodhull became “Samuel Culper Sr.”
Townsend’s business activities gave him a legitimate reason to spend time in British-controlled Manhattan and put him in a better position to obtain information without making the repeated suspicious trips that had endangered Woodhull.
Some popular accounts describe Townsend as a reporter for Loyalist newspaper publisher James Rivington, but historians have questioned that claim. What is clear is that Townsend operated a business in Manhattan and became a major source of information for the Culper network.
His identity was protected so carefully that George Washington did not know who Culper Jr. actually was.
Townsend died in 1838 with his Revolutionary War role still largely unknown. He is buried at Fort Hill, also known as Townsend Cemetery, in Oyster Bay.
George Washington did not know all of his own spies
Secrecy within the Culper network extended beyond keeping information from the British.
Members often knew only the people they needed to know.
Aliases and code numbers were used instead of real names, and Washington himself did not know the identities of everyone gathering intelligence for him.
That was deliberate.
If a courier was captured or a letter intercepted, limited knowledge of the network made it harder for the British to identify everyone involved.
The arrangement closely resembles what modern intelligence services call compartmentalization: limiting information to people who actually need it.
The Culper Spy Ring used codes and invisible ink
The spies increasingly developed more sophisticated methods for hiding both their information and their identities.
Benjamin Tallmadge created a numerical codebook containing hundreds of substitutions for common words, people and places.
In the code:
- George Washington was 711
- Benjamin Tallmadge was 721
- Abraham Woodhull was 722
- Robert Townsend was 723
- Caleb Brewster was 725
- New York was 727
- Setauket was 729
The spies also used invisible ink, which they called “stain.”
The special ink was developed by physician and chemist James Jay, brother of John Jay, who later became the first chief justice of the United States.
A second chemical solution, called the “counterpart,” revealed the hidden writing.
Messages could therefore appear to contain ordinary correspondence while intelligence was written invisibly between the visible lines or elsewhere on the page.
The Culper codebook survives today.
What intelligence did the Culper Spy Ring provide?
The Culper network reported on British troop movements, troop strength, naval activity, fortifications and military preparations in and around New York.
One of its important early contributions involved intelligence about British plans against French forces after France entered the war on the American side.
The network also provided information about a British counterfeiting operation targeting Continental currency.
Counterfeit money was a serious threat because the Continental government was already struggling with inflation and confidence in its paper currency.
Reports supplied through the network gave Washington a more consistent picture of what British forces were doing inside territory he could not directly observe.
Did the Culper Spy Ring uncover Benedict Arnold’s treason?
The Culper Spy Ring is frequently credited with helping expose Benedict Arnold’s attempt to surrender West Point to the British, but the historical record is more complicated.
Arnold secretly negotiated with British intelligence officer Major John André in 1780. André was eventually captured in Westchester County carrying incriminating documents connected to the plot.
Some historians and popular histories credit Culper intelligence with contributing to the unraveling of the conspiracy. Others argue that later accounts have overstated the network’s direct role.
It is therefore more accurate to say the Culpers operated within the intelligence environment surrounding Arnold and André rather than claiming they single-handedly discovered the plot.
Their documented work gathering British military intelligence was substantial without needing to give them sole credit for Arnold’s exposure.
Who was Agent 355?
Few parts of the Culper story have generated more speculation than the mysterious “Agent 355.”
The surviving Culper correspondence contains the number 355 only once.
In the network’s numerical code, 355 simply meant “lady.”
In an August 1779 letter, Abraham Woodhull wrote that he expected assistance from “a 355 of my acquaintance.”
Over time, that reference developed into the story of a secret female operative known as Agent 355. Some versions describe her as a socially connected woman in British-occupied Manhattan who supplied valuable intelligence and may even have moved within the circle of John André.
There is no documentary evidence establishing such a person as a formal Culper spy called Agent 355.
Historians continue to debate who the unnamed woman was and what assistance she provided. Some have suggested Anna Strong. Others believe she could have been another woman entirely.
The mystery remains largely because one short reference in a coded letter has produced more than two centuries of speculation.
Did Anna Strong really signal the Culper spies with her laundry?
Anna Smith Strong of Setauket is one of the best-known women associated with the Culper Spy Ring.
According to longstanding local tradition, Strong developed an ingenious signaling system using laundry.
The story holds that a black petticoat hanging on her clothesline indicated that Caleb Brewster had arrived in the area. The number of white handkerchiefs hanging beside it supposedly told Abraham Woodhull which of several coves Brewster was using.
It has become one of the most famous stories connected to the Culper Ring.
There is one problem: no surviving Culper letter documents the clothesline system.
Long Island historians disagree over how much of the story is fact and how much is family tradition that grew over time. Some historians believe Strong assisted the network and that the clothesline story preserves a real signaling method. Others regard the specific petticoat-and-handkerchief system as folklore.
Strong’s husband, Selah Strong, was arrested by British authorities during the war, and the Strong family had deep connections throughout the Setauket community.
Anna Strong remains closely associated with the Culper story, but describing the clothesline signal as documented fact goes further than the surviving evidence allows.
Caleb Brewster carried intelligence across Long Island Sound
Caleb Brewster supplied the maritime link in the Culper chain.
A Setauket native and experienced seaman, Brewster used whaleboats to transport messages between Long Island and Connecticut.
His job also went well beyond quietly carrying letters.
Brewster participated in raids and skirmishes on Long Island Sound, attacking British and Loyalist vessels and disrupting enemy activity.
After the Revolutionary War, he joined the United States Revenue Cutter Service, an early predecessor of the U.S. Coast Guard.
His family also left another surviving connection to the Culper era in Setauket.
The 1665 Brewster House still stands in Setauket
The Brewster House in East Setauket dates to about 1665 and is considered the oldest surviving house in the Town of Brookhaven.
Caleb Brewster’s cousin Joseph Brewster operated a tavern and inn there during the Revolutionary War.
British soldiers were among the people entertained at the tavern, while Joseph had family and social connections to members of the Patriot intelligence network. The exact extent of his own involvement with the Culper operation is less certain than some popular accounts suggest.
Joseph Brewster later served on a committee associated with the road that became Route 25A.
Today, that route carries another name closely connected to the spies: the Washington Spy Trail.
John Graves Simcoe nearly caught Abraham Woodhull
Viewers of AMC’s “TURN: Washington’s Spies” will recognize John Graves Simcoe as one of the series’ principal antagonists.
The television version took substantial liberties with his character and with other parts of Culper history, but the real Simcoe did pose a genuine threat to Woodhull.
As commander of the Queen’s Rangers, Simcoe came to Setauket in 1779 after receiving information about Woodhull.
Woodhull escaped arrest because he was away when Simcoe arrived.
There is another peculiar Long Island connection involving Simcoe.
Simcoe Street in Oyster Bay leads toward the Townsend family cemetery where Robert Townsend is buried. Simcoe and his Queen’s Rangers had occupied the Townsend family home, now Raynham Hall Museum, during the war.
On Feb. 14, 1779, Simcoe presented Robert Townsend’s sister Sarah “Sally” Townsend with a lengthy romantic poem.
Raynham Hall preserves it as the first documented Valentine in the United States.
Benjamin Tallmadge also led a major raid across Long Island
Tallmadge’s Long Island activities were not limited to running spies.
In November 1780, he led a force across Long Island Sound from Connecticut and landed near Cedar Beach in Mount Sinai.
His men then marched roughly 20 miles across Suffolk County to the Manor of St. George in what is now Shirley, where British and Loyalist troops had established a fortified position.
Tallmadge’s force captured the fort and destroyed military supplies.
On the return trip north, his men also burned British hay stores at Coram, depriving enemy forces of supplies needed for their horses.
The route is commemorated today as the Tallmadge Trail.
The identity of Samuel Culper Jr. remained hidden for generations
The Culper network was so successful at protecting Robert Townsend’s identity that his role remained unknown long after his death.
Long Island historian Morton Pennypacker eventually identified Townsend as Samuel Culper Jr. in the 1930s.
Pennypacker announced the identification in 1930 and later supported it through handwriting analysis. His 1939 book, “General Washington’s Spies on Long Island and in New York,” helped bring the story of the Culper network to a much wider audience.
The fact that one of Washington’s most important intelligence sources could remain unidentified for roughly 150 years says a great deal about how carefully the network protected its secrets.
Did the Culper Spy Ring win the Revolutionary War?
Claims that the Culper Spy Ring single-handedly saved the American Revolution go beyond what historians can establish.
Washington relied on many intelligence sources, military commanders, soldiers, foreign allies and other networks during the war.
The Culper spies nevertheless filled an important gap.
They gave Washington regular information from British headquarters in New York, reported on military movements and preparations, developed secure communication methods and operated for years inside occupied territory without the British successfully destroying the network.
Even the CIA now points to the Culpers as early practitioners of techniques that remain fundamental to intelligence work, including aliases, codes, operational cover and limiting information to those who needed it.
Their importance does not depend on claiming that they won the war by themselves.
Long Island’s Route 25A is now the Washington Spy Trail
The Culper story is unusually accessible because so many locations associated with it survive.
In 2017, New York officially designated approximately 50 miles of Route 25A between Great Neck and Port Jefferson as the Washington Spy Trail.
Twenty-six signs were installed along the corridor highlighting its connection to Revolutionary War history.
The route reflects several layers of the story. Culper couriers used roads along Long Island’s North Shore, and George Washington traveled through the region during his 1790 presidential tour.
Today, visitors can explore surviving Culper-related locations in Setauket and Oyster Bay, including the Brewster House, Setauket Presbyterian Church and Cemetery, Raynham Hall Museum and Townsend Cemetery.
Guided and self-guided Culper tours are also available in the Three Village area.
How accurate was “TURN: Washington’s Spies”?
AMC’s “TURN: Washington’s Spies,” which aired from 2014 to 2017, brought considerably more attention to Abraham Woodhull, Benjamin Tallmadge and the Culper network.
It was a historical drama rather than a documentary.
Among other changes, the series altered timelines, relationships and personalities and invented a romance between Abraham Woodhull and Anna Strong that is not supported by the historical record.
The interest generated by the show also inspired extensive fact-checking. The independent “TURN to a Historian” project examined episodes, characters and events to separate documented Culper history from television fiction.
For Long Island, the popularity of the series helped introduce a national audience to a Revolutionary War story that had been centered in Setauket for more than two centuries.
Long Island’s surviving connection to America’s early spy history
The Culper Spy Ring operated in secrecy because its members had no other safe choice.
Setauket and Oyster Bay were inside British-controlled territory. Discovery could mean imprisonment or execution, and at least one central member of the network narrowly avoided capture.
Yet many of the places connected with the story remain recognizable today.
Abraham Woodhull is buried in Setauket. Robert Townsend rests at Fort Hill in Oyster Bay. The Brewster House still stands along Route 25A. Raynham Hall preserves the home occupied by British officers while a member of the Townsend family secretly gathered intelligence for Washington.
And the road connecting many of those communities is now formally marked as the Washington Spy Trail.
The methods have changed considerably since 1778, but Long Island’s role in the history of American intelligence began with farmers, merchants, tavern keepers, riders and sailors carrying information through an occupied island without revealing who they really were.
