We are endlessly fascinated by stories of coded messages, espionage, and intelligence found in the historical records of the National Archives. Join us as we crack the code in this week’s newsletter to bring you stories of spies, camouflage, and cryptography found in the National Archives Catalog!

Substitution Cipher Wheel
Black and white World War II poster showing women studying detection equipment in an advertisement for the Women's Army Corps

L: Substitution Cipher Wheel, 1865. National Archives Identifier 3854702
R: WACS with the Army Air Forces. National Archives Identifier 515997

World War I Camouflage

When the United States entered World War I in 1917, a group of female art students in New York City joined the National League for Women’s Service and trained to serve in the Camouflage Department of the United States Navy. Students studied the environment and tested camouflage suits, which were designed to keep the wearer safe from detection and blend in with the surrounding environment. Learn more on the Unwritten Record blog.

Black and white photograph of group of women dressed in camouflage suits studying the outdoor environment among rocks and trees

The Women’s Camouflage Reserve Corps of the National League for Women’s Service, tested out camouflage suits at Van Cortlandt Park, New York, during WW1. National Archives Identifier 45568270

Black and white photograph of group of four women dressed in camouflage suits. One women lies on the ground while another helps her into a suit designed to resemble rock formation
Women's Activities, Women's Reserve Camouflage, 10/11/1918. National Archives Identifier 45568262

During WWI, allied forces painted naval ships in abstract patterns with bright colors to make it difficult for German U-boats to determine the speed and precise location of the ship. Beginning in March of 1918, the United States Navy painted a total of 1250 vessels with the unique design. Out of the 96 ships sunk by Germans after March 1918, only 18 of the ships were camouflaged. Learn more on the Unwritten Record blog.

Ship drawing showing abstract colors and designs painted on the outside of the ship for camouflage
British Camouflage, Type 17, Design C, Port. National Archives Identifier 56070827
Black and white photograph of group of women painting a battleship with camouflage in New York City
Women's Activities, Women's Reserve Camouflage, 1918. National Archives Identifier 45568250

The Zimmermann Telegram

In January 1917, British cryptographers deciphered a telegram from German Foreign Minister Arthur Zimmermann to the German Minister to Mexico, Heinrich von Eckhardt, offering United States territory to Mexico in return for joining the German cause. This message helped draw the United States into the war and thus changed the course of history. Find teaching activities and more with Educator Resources.

Western Union telegram written in code
Letter deciphering the Zimmermann Telegram

L: Zimmermann Telegram as Received by the German Minister to Mexico, 3/1/1917. National Archives Identifier 302025

R: Letter from Ambassador Walter Page to the Secretary of State, Original Decipher of the Zimmermann Telegram, 3/2/1917. National Archives Identifier 302024

Code Talkers

During World Wars I and II, the U.S. military needed to encrypt communications from enemy intelligence. American Indians had their own languages and dialects that few outside their tribes understood; therefore, their languages were ideal encryption mechanisms. Over the course of both wars, the Army and the Marine Corps recruited hundreds of American Indians to become Code Talkers. Records at the National Archives document the origins of this program and the group’s wartime contributions.

Find more information and resources regarding Code Talkers on our website. Read more on the Unwritten Record blog: Navajo Code Talkers, and on History Hub: The Unbreakable Choctaw Code.

Black and white photograph of two Navajo code talkers with radio equipment
Photograph of Navajo Indian Code Talkers Preston Toledo and Frank Toledo, 7/7/1943. Photographer: Ashman. National Archives Identifier 100378007

The Pumpkin Papers

These canisters contained film rolls known as the Pumpkin Papers, which were used in the House Committee on Un-American Activities investigation of Alger Hiss. The canisters and film stored inside were found inside a pumpkin on the farm of Whittaker Chambers in Maryland. Learn more about the United States of America vs. Alger Hiss.
Image of four film canisters from the HUAC investigation of Alger Hiss
Records Relating to the Investigation of Alger Hiss, 1948 - 1951, Pumpkin Papers Canisters, 1948. National Archives Identifier 7797870

Rose Greenhow

Rose O'Neal Greenhow (1817-1864) was a popular socialite in Washington, DC, and a spy for the South during the Civil War. During the Civil War, Greenhow wrote ciphered messages to the Confederates and provided information about Union military plans. Confederate President Jefferson Davis credited her with helping the South win the First Battle of Bull Run. Greenhow provided a message about the Union troop's movements in time for Brigadier Generals Beauregard and Johnston to meet at Manassas, Virginia. A young woman working with Greenhow named Betty Duvall carried the message wrapped in a tiny black silk purse and wound up in a bun of her hair. Learn more about the Seized Correspondence of Rose O'Neal Greenhow.

Letter written in cipher
Letter written in cipher
Letter Written in Cipher on Mourning Paper by Rose Greenhow. National Archives Identifier 1634036
Start your research on History Hub

Have a question?  Find your answer on History Hub!

For those looking to conduct research or learn more about cryptography, espionage and intelligence-related records, we encourage you to browse recent posts and questions on History Hub. Recent posts include:


Find more questions on the Central Intelligence Agency (CIA) and Office of Strategic Services (OSS)!

Color image of a battleship disguised as an island.

Battleship Disguised as an Island. National Archives Identifier 6997114

Citizen Archivist Opportunities
Document showing mediterranean passport for the ship Falcon signed by Andrew Jackson and Martin Van Buren

You can help us unlock history! Take a look at our latest Citizen Archivist missions, and jump in to participate! Our current missions include records about Tennessee Valley Authority Family Removal and Population Readjustment Case Files, Protection from Pirates, State Department Briefs Files, and more. Every contribution you make helps make these records easier to find in our Catalog.

New to the Citizen Archivist program? Learn how to register and get started.
Already have an account? Login here.

The Catalog Newsletter

Learn about newly added records and receive tips on using the Catalog's features, functionality, and guides. The National Archives Catalog is the online public portal to our records where you can learn more about our holdings. This email newsletter is delivered on a biweekly basis. Subscribe to the National Archives Catalog Newsletter