The Mystery Of Agent 355, The Unknown Woman Who Spied For General George Washington

Published November 13, 2021
Updated January 19, 2024

Spies in the Continental Army wrote of a highly capable operative known only as Agent 355, and though some historians doubt her existence, others think she may have changed the course of the Revolutionary War.

In 1776, a plucky group of rebels in colonial America fought against the powerful empire of Great Britain to secure their independence in the Revolutionary War. And one way these revolutionaries did so was through a top-secret spy network.

Led by General George Washington, these spies created codes and scrawled messages in invisible ink. They crossed behind enemy lines and sometimes used laundry to signal their compatriots. Most importantly, they risked their lives for the revolution.

And one of the most intriguing of Washington’s spies remains unknown today. More than two centuries later, we still don’t know the name of the mysterious Agent 355, a woman said to have spied on the British.

That is, if she really existed.

The Culper Ring, George Washington’s Secret Spy Network

Agent 355

Wikimedia CommonsAn 1863 depiction of the still-unknown Agent 355 from Harper’s Weekly.

Spies played a critical role in winning the American Revolution. Outnumbered and outgunned, Washington relied on his intelligence advantage to defeat the British.

Women, in particular, were often Revolutionary spies. One woman named Anna Strong who lived on Long Island under British occupation during the war, strategically hung petticoats and handkerchiefs on her clothesline to signal where other spies had hidden documents.

But Strong didn’t work alone. She was part of the so-called Culper Ring, the most important spy network during the Revolution, and of which a shadowy but remarkable spy known as Agent 355 was also reportedly a member.

General George Washington

Charles Willson Peale/Brooklyn MuseumA 1776 portrait of General George Washington.

Formed in 1778 to gather intel from the British-held territory in New York, the Culper Ring ran a tight-lipped organization, where even Washington didn’t know the identity of the spies. Instead, each member of the Culper Spy Ring was given numerical code. General Washington, for instance, was 711.

Culper spies posed as Loyalists to win British trust, and even uncovered Benedict Arnold’s treachery. In fact, it is believed that none other than Agent 355 had direct contact with Arnold — and might have been the driving force behind bringing his crimes to light.

What Did Agent 355 Do?

Culper Ring Cipher

Benjamin Tallmadge/Mount VernonA page from the Culper Spy Ring code book listing ciphers.

The Culper code book officially listed the ciphers for 763 names, places, and things, like code 219 which meant gun or 223 which meant gold. And 355, which normally meant “lady,” but also seemed to refer to a still-unknown agent.

In an Aug. 15, 1779 letter, a member of the Culper Spy Ring named Abraham Woodhull wrote to General Washington, mentioning an anonymous woman, “I intend to visit 727 [New York] before long and think by the assistance of a 355 of my acquaintance, shall be able to out wit them all.”

Later research showed that Woodhull was indeed accompanied by a female agent who was involved with the Culper Spy Ring. One theory claimed that this woman was actually the lover of another spy.

Even later, a 1948 newspaper article seemed to suggest that this unknown “Agent 355” was indeed real and have even met a tragic ending:

Girl Who Spied for Washington Died on Wallabout Prison Ship. Say Child Was Born to Her in Hulk of Vessel

According to this same report, the British captured Agent 355 in the final years of the war. They transported her to the prison ship Jersey, one of many floating prisons in New York Harbor. As many as 11,000 prisoners died in British prison ships like this during the war.

When the British captured Agent 355, she was reportedly pregnant. After giving birth, Agent 355 died on the prison ship. Except with only one reference in historical records to Agent 355, it’s impossible to know whether this story is true.

Was This Unknown Female Agent Actually Real?

When scholars looked into the story of a secret female agent who died aboard a prison ship, the earliest reference came from the 1948 work of Suffolk County historian Morton Pennypacker. Pennypacker correctly identified other members of the Culper Spy Ring based on handwriting analysis, but he provided little evidence for the tragic tale of Agent 355.

Brooklyn Map

Bernard Ratzer/Wikimedia CommonsA map of Brooklyn from 1766. During the Revolutionary War, the British seized New York and made it their headquarters.

So was Agent 355 real?

We likely won’t ever know the truth about Agent 355, but historians have several theories about her identity. One claims that Agent 355 was actually Anna Strong, and another posits that 355 was no agent at all, but an informant who met with Abraham Woodhull and never officially joined the spy ring.

Though we may never identify Agent 355, there was nonetheless one fearless woman — of many — who contributed to the Revolutionary War.

Next, read about another master of espionage, James Armistead Lafayette, the enslaved man who became a double agent to help the Americans win the Revolutionary War. Then, read the legend of Molly Pitcher, the woman who supposedly fought on the frontlines of the Revolutionary War.

Genevieve Carlton
Genevieve Carlton earned a Ph.D in history from Northwestern University with a focus on early modern Europe and the history of science and medicine before becoming a history professor at the University of Louisville. In addition to scholarly publications with top presses, she has written for Atlas Obscura and Ranker.
John Kuroski
John Kuroski is the editorial director of All That's Interesting. He graduated from New York University with a degree in history, earning a place in the Phi Alpha Theta honor society for history students. An editor at All That's Interesting since 2015, his areas of interest include modern history and true crime.
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Carlton, Genevieve. "The Mystery Of Agent 355, The Unknown Woman Who Spied For General George Washington.", November 13, 2021, Accessed May 24, 2024.