In postal mail, a return address is an explicit inclusion of the address of the person sending the message. It provides the recipient (and sometimes authorized intermediaries) with a means to determine how to respond to the sender of the message if needed. The return address need not include a sender's name, but should include address or P.O. box details in the same way as the delivery address should. In some countries, the return address is conventionally located in the upper left hand corner of the envelope, card, or label. In the United Kingdom, the return address is usually placed on the reverse of the envelope, near the top.
Businesses often use envelopes preprinted with a return address. Many individuals have sheets of adhesive labels preprinted with their home address to affix to their correspondence. Charities sometimes include such sheets in mailshots. Rolls of Return Address Labels can be purchased from companies that sell personalized labels to provide individuals an easy way to peel and stick return address labels to their envelopes.
The return address is not required on postal mail. However, lack of a return address prevents the postal service from being able to return the item if it proves undeliverable; such as from damage, postage due, or invalid destination. Such mail may otherwise become dead letter mail.
Should the return address be of a different state or country, the mail may be routed through that location for ease of return.
The return address has been used on U. S. postage since the 1880s. As pressure printing became more commonplace in the early 1900s, labels became cheaper and more easily distributed. The profession that dealt with making these labels was called lithography. In the 1950s in the U. S., more and more mail was not making it to intended recipients, and as a result of the lack of a return address, said mail ended up in the dead letter office. With this rise in dead mail, the post office pleaded for people to use return addresses. Even after this, the public still tended to neglect adding a return address. This prompted the postmaster to inform the public that mail with no return address would be less of a priority than mail with a return address. Still, the public did not widely use a return address until the 1960s when companies began to offer deals for pre-printed return labels such as 2,500 labels for $2.00. They became more popular with the invention of label dispensers. With the invention of the personal computer, software enabled people to print their own labels. As e-mail began to overtake written mail, the return address became automatic in an e-mail.