The United States Postal Service started a dead letter office in 1825 to deal with undeliverable mail. Approximately 57 million items end up in this office every year, where enclosed items of value are removed and the correspondence is destroyed. When enclosed items are deemed to be of obviously exceptional value, efforts may be made to return them to the sender. Items of value that cannot be returned are sold at auction. Except for pornography and firearms, everything that can be lost in the mail is included at auction. The auctions also occasionally include items seized by postal inspectors and property being retired from postal service.
These facilities are now known as mail recovery centers (MRC). Other former names include dead letter branch and dead parcel branch. These facilities are not unique to the US Postal Service, and go by different names in other countries. The USPS mail recovery centers are located in Atlanta, Georgia and Saint Paul, Minnesota. An MRC in San Francisco, California was closed on September 13, 2002.. Since 2004, the postal auctions have been held only in Atlanta. These auctions include not only material lost in the US but also material from other national postal authorities who consign them to the USPS for auction.
The Canadian equivalent of the dead letter office is located in Mississauga, Ontario.
- One famous fictional employee of the dead letter office is Bartleby, the eponymous character of Herman Melville's "Bartleby, the Scrivener: A Story of Wall-Street."
- R.E.M. released a compilation of b-sides and rarities entitled Dead Letter Office.
- In the film Miracle on 34th Street, two mail sorters handle a letter addressed to "Kris Kringle" at the New York City courthouse, and decide to deliver all the Santa Claus mail now in the dead letter office to the courthouse, where a man calling himself Kris Kringle is facing a mental competency hearing. The man's attorney uses the huge volume of mail as evidence that the federal government recognizes his client as "the one-and-only Santa Claus."
- The term "dead letter office" may be used in non-postal offices, in reference to any room of disused materials resembling a dead letter office.
- Horror writer Clive Barker's book The Great and Secret Show features segments centered around the dead letter office at Omaha, Nebraska.
- Dead Letter Office are an alternative rock band based in the United Kingdom
- The Australian film Dead Letter Office focuses on a woman who gets a job at a dead letter office in order to contact her long-lost father.
- In The Simpsons episode "Sunday, Cruddy Sunday," Springfield Elementary visits their local Post Office and are treated to a piece of undeliverable mail from the dead letter office as a souvenir.
- The 1996 film Dear God, in which a character played by Greg Kinnear, working in a post office, responds to letters written to God
- In Australia, the postal authority (Australia Post) has renamed the "Dead Letter Office" the "Mail Redirection Centre" although documentation as recent as September 2007 still refers to it as the "Dead Letter Office".
- In Terry Pratchett's book Making Money, the Postmaster Moist finds Lord Vetinari, the Patrician and ruler of the city, wandering around the Dead Letter office of the Ankh-Morpork post office. Vetinari is able to deduce a letter labeled "Dat Place wit dem grete Bunz" is one of his favorite bakeries. (In the U.S. edition, the address is "Duzbuns Hopsit pfarmerrsc", and it is the "Blind Letter Office".)