Entitled: "Ranch mailbox near Farson, Wyoming." Before the introduction of rural free delivery (RFD) by the Post Office in 1896, many rural residents had no access to the mail unless they collected it at a post office located many miles from their homes or hired a private express company to deliver it. For this reason, mailboxes did not become popular in rural America until curbside RFD mail delivery by the Post Office was an established service. In 1923 did the Post Office finally mandate that every household install a mailbox or mail slot in order to receive home delivery of mail. Originally designed only for incoming mail delivery, curbside mailboxes were soon fitted with a semaphore or signal flag mounted on an attached arm to signal the postman of outgoing mail, but also by the postman to inform the recipient that incoming mail had been delivered - a convenience to all during periods of freezing or inclement weather. Curbside mailboxes located on a rural route or road and sited at the intersection of the road with each recipient's carriageway or private drive allowed limited numbers of mail carriers to deliver mail to many widely scattered farms and ranches in a single day. Photographed for Farm Security Administration by Marion Post Wolcott, 1941.