

En esta noticia
In the United States, the small flag that sticks out of mailboxes installed at the curb serves a practical function: to alert the mail carrier that there is outgoing mail to pick up.
The mechanism is part of the United States Postal Service (USPS) delivery system and allows mail to be handled without the worker having to exit the vehicle at each stop.
What is the small flag on U.S. mailboxes for
The mailbox flag, known in English as “mailbox flag or carrier signal flag”, works as a visual signal for the mail carrier. When it is raised, it indicates that there is outgoing mail inside the mailbox and it must be picked up.
The signal also helps distinguish a mailbox that only receives mail from one that allows both receiving and sending mail.
When should it be raised?
The flag should be raised when outgoing mail is placed inside the mailbox for the mail carrier to pick up. The procedure is simple:
- Place the letter or envelope inside the mailbox, properly prepared for mailing.
- Raise the outer flag to indicate that there is mail awaiting pickup.
- Leave the signal visible from the mail carrier’s route.
- Wait for the postal worker to collect the mail during their regular route.

Does the mail carrier lower the flag?
Yes. According to the technical standard of the USPS, when the flag is activated to indicate that there is outgoing mail, it must remain in that position until the mail carrier lowers it.
Do all mailboxes have a flag?
No. The USPS distinguishes between full-service and limited-service mailboxes, a classification that depends, among other things, on the presence of the signal flag.
The technical standard defines contemporary and traditional mailboxes with flags as full-service units. By contrast, those that do not include this mechanism are considered limited-service and are intended for customers who do not want the mail carrier to collect their outgoing mail.
The same specification warns that unless the carrier has mail to deliver, they will not stop at limited-service mailboxes.
What color should the flag be
Although the mailbox can be different colors, the flag must meet specific requirements. The USPS standard establishes that it can be any color except shades of green, brown, white, yellow, or blue.
In addition, the flag must contrast with the predominant color of the mailbox. The rule indicates that the preferred color is fluorescent orange due to its visibility.
It is also important to know that the flag must be installed on the right side of the mailbox when viewed from the front; in this way, the mail carrier lowers it without having to apply excessive force.
