After the introduction of stamps, people wanted a more convenient place to drop-off their mail than the post office. In the 1850s, the Post Office Department began installing collection mailboxes outside of post offices and on street corners in large cities. People can drop their letters in these mailboxes throughout the day, and the postal service collects the accumulated mail at specific times, usually marked on the box.
Collection boxes were initially mounted on lampposts. Albert Potts, a Philadelphia iron manufacturer, patented the first of these mailboxes on March 9, 1858 (patent number 19,578). As mail volume grew, the Post Office Department gradually replaced these small boxes.
The four-footed, free-standing mailbox was first suggested in 1894, and it quickly became a familiar sight on city street corners. The proliferation of automobiles influenced mailbox design in the late 1930s, when an extension chute or 'snorkel' to curbside boxes was adopted.
At the beginning of the twenty-first century, changes in consumer habits, such as online bill paying, have decreased the volume of first-class mail and, therefore, the necessity of many collection boxes. In addition, fears of terrorism have resulted in the removal of almost 7,000 street boxes. Although the number of collection mailboxes has declined, the U.S. Postal Service continues to develop new mailbox designs to adapt to the changing environment.
Allison Marsh, National Postal Museum