Postal censorship is the inspection or examination of mail, most often by governments. It can include opening, reading and total or selective obliteration of letters and their contents, as well as covers, postcards, parcels and other postal packets. Postal censorship takes place primarily but not exclusively during wartime (even though the nation concerned may not be at war, e.g. Ireland during 1939-1945) and periods of unrest, and occasionally at other times, such as periods of civil disorder or of a state of emergency. Both covert and overt postal censorship have occurred.
Historically, postal censorship is an ancient practice; it is usually linked to espionage and intelligence gathering. Both civilian mail and military mail may be subject to censorship, and often different organisations perform censorship of these types of mail. In 20th century wars the objectives of postal censorship encompassed economic warfare, security and intelligence.
Military mail 
Military mail is not always censored by opening or reading the mail, but this is much more likely during war time and military campaigns. The military postal service is usually separate from civilian mail and is usually totally controlled by the military. However both civilian and military mail can be of interest to military intelligence, which has different requirements from civilian intelligence gathering. During wartime, mail from the front is often opened and offending parts blanked or cut out, and civilian mail may be subject to much the same treatment.
POW and Internee mail 
POW and internee mail is also subject to postal censorship, which is permitted under Articles 70 and 71 of the Third Geneva Convention (1929–1949). It is frequently subjected to both military and civil postal censorship because it passes through both postal systems.
Civil mail 
Until recent years, the monopoly for carrying civilian mails has usually been vested in governments and this has facilitated their control of postal censorship. The type of information obtained from civilian mail is different from that likely to be found in military mail.
Countries known to have enacted postal censorship 
Throughout modern history various governments, usually during times of war, would have to inspect mail coming into or leaving the country so as to prevent an enemy from corresponding with unfriendly entities within that country. There exist also many examples of prisoner of war mail from these countries which was also inspected or censored. Censored mail can usually be identified by various postmarks, dates, postage stamps and other markings found on the front and reverse side of the cover (envelope). These covers often have an adhesive seal, usually bearing special ID markings, which were applied to reclose and seal the envelope after inspection.
Britain & American colonies 
During the years leading up to the American Revolution, the British monarchy in the American colonies manipulated the mail and newspapers sent between the various colonies in an effort to prevent them from being informed and from organizing with each other. Often mail would be outright destroyed.
American Civil War 
During the American Civil War both the Union and Confederate governments enacted postal censorship. The number of Union and Confederate soldiers in prisoner of war camps would reach an astonishing one and a half million men. The prison population at the Andersonville Confederate POW camp alone reached 45,000 men by the war's end. Consequently there was much mail sent to and from soldiers held in POW installations. Mail going to or leaving prison camps in the North and South was inspected both before and after delivery. Mail crossing enemy lines was only allowed at two specific locations.
Pre–World War I 
In Britain, the General Post Office was formed in 1657, and soon evolved a "Secret Office" for the purpose of intercepting, reading and deciphering coded correspondence from abroad. The existence of the Secret Office was made public in 1742 when it was found that in the preceding 10 years the sum of £45,675 (a huge amount at that time) had been secretly transferred from the Treasury to the General Post Office to fund the censorship activities. In 1782 responsibility for administering the Secret Office was transferred to the Foreign Secretary and it was finally abolished by Lord Palmerston in 1847.
World War I 
During the Great War (WWI) Postal censorship occurred in Great Britain, France, Germany and other various countries involved with that war.
Between the wars 
Following the end of World War I there were some places where postal censorship was practiced. During 1919 it was operating in Austria, Belgium, Canada, German Weimar Republic and the Soviet Union. Other conflicts during which censorship existed were the Italian occupation of Ethiopia (1935–36) and especially during the Spanish Civil War of 1936-1939.
World War II 
During World War II both the Allies and Axis instituted postal censorship of civil mail. The largest organisations were those of the United States, though the United Kingdom employed about 10,000 censor staff while Ireland, a small neutral country, only employed about 160 censors.
British censorship was mainly based at Aintree (near Liverpool) with nearly 20 other censor stations around the country. Additionally the British censored colonial and dominion mail at censor stations in the following places:
- Dominions: Australia, Canada, Newfoundland, New Zealand, Southern Rhodesia (not a dominion but supervised by the Dominion office) and Union of South Africa
- Colonies: Aden, Antigua, Ascension Island, Bahamas, Barbados, Bermuda, Ceylon, Cyprus, Dominica, Egypt, Falkland Islands, Fiji, Gambia, Gibraltar, Gilbert and Ellice Islands, Gold Coast, Gibraltar, Granada, British Guiana, British Honduras, Hong Kong, Jamaica, Kenya, Malaya, Malta, Mauritius, Montserrat, New Hebrides, Nigeria, North Borneo, Northern Rhodesia, Nyasaland, Palestine, Penang, St. Helena, St. Lucia, St. Kitts and Nevis, St. Vincent, Sarawak, Seychelles, Sierra Leone, British Solomon Islands, Somalia, Sudan, Tanganyika, Trinidad, Tonga, Uganda, Virgin Islands and Zanzibar,
The USA censor staff count rose to 14,462 by February 1943 in the censor stations they opened in New York, Miami, New Orleans, San Antonio, Laredo, Brownsville, El Paso, Nogales, Los Angeles, San Francisco, Seattle, Chicago, San Juan, Charlotte Amalie, Balboa, Cristóbal, David, Panama and Honolulu.
Both blacklists and whitelists were employed to observe suspicious mail or listed those whose mail was exempt from censorship. The United States blacklist, known as U.S. Censorship Watch List, contained 16,117 names.
Post–World War II 
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See also 
- American Civil War prisoner of war mail
- Black room
- Cabinet noir
- Israeli Military Censor
- Mail censorship in Ireland
- Secrecy of correspondence
- United States Office of Censorship
References and sources 
- Pushing the Envelope (retrieved 21 August 2006)
- The (US) Postal Monopoly (retrieved 21 August 2006)
- American Heritage Magazine, The U.S. Post Office, 1775-1974
- New York Times/ABOUT.COM
- "American Civil War: POW camp at Andersonville ". New York Times, about-com. Retrieved 17 November 2010.
- "Civilian Flag-of-Truce Covers". S.N.P.M.
- "Prisoner mail exchange ". Prisoner of War mail, Smithsonian National Postal Museum. Retrieved 17 November 2010.
- Hemmeon, Joseph Clarence (1912). The history of the British post office. Cambridge, MA: Harvard University. p. 46.
- "Between the Wars - Italian Occupation of Ethiopia". Postalcensorship.com. Retrieved 2008-10-24.
- Ó Drisceoil, Donal (1996). Censorship in Ireland, 1939-1945. Cork University Press. p. 62. ISBN 978-1-85918-074-7.
- "Civilian Agency Records: Records of the Office of Censorship (RG 216)". National Archives and Records Administration. Retrieved 2010-11-22.
Wolter, Karl Kurt (1965). Die Postzensur: Band I - Vorzeit, Früheit und Neuzeit (bis 1939). Munich: Georg Amm.
Herbert, E.S., & des Graz, C.G., ed. (1996). History of the Postal and Telegraph Censorship Department 1938–1946 Volume I & II. Civil Censorship Study Group by permission of Public Records Office, Kew, UK.
Harrison, Galen D. (1997). Prisoners' Mail from the American Civil War. Dexter, MI: Galen D. Harrison (?).
- History comes to life with censored covers Linn's Stamp News
- Postalcensorship.com Website devoted to postal censorship with many examples of censored mail
- Civil Censorship Study Group
- Forces Postal History Society
- Military Postal History Society