What Are Blue Mailboxes For? (Explained)

If you are in a big city or a busy town, you may have seen a few blue mailboxes strategically placed in the area.

These blue mailboxes are USPS Collection Boxes, also known as USPS Drop Boxes.

You may typically see these boxes in large cities like San Antonio, Denver, Boston, and New York. You will mostly like to see one of these USPS mailboxes in largely populated cities every couple of blocks or so.

In rural areas, they are not that common because not a lot of people use them in these areas:

Here is What Blue Mailboxes Are for:

These blue mailboxes in cities are USPS Collection Boxes or Drop Boxes. The US Postal Service provides these mailboxes. These mailboxes function as drop-off points for mail and packages. Anyone can use them to send mail and packages as long as they meet the guidelines.

Are USPS Drop Boxes Always Blue?

Back in the day, USPS Drop Boxes came in red, blue, and white to mimic the colors of the United States flag.

When the USPS was reorganized in 1971, the color was changed to blue. The change in color of the mailboxes was part of the rebranding.

Nowadays, all USPS Drop Boxes are always blue.

All USPS Drop Boxes have to be in the same color to be easily recognizable. The color makes these boxes easy to spot, so if someone sees a blue mailbox on the sidewalk, they would right away that it is a USPS Drop Box.

Making these boxes easily visible saves people from the hassle of having to look for one whenever they have outgoing mail to send. It also saves people from a trip to the local post office.

What Kind Of Mail CAN You Put In Blue Mailboxes?

There are certain guidelines for what kind of mail you can drop off in these blue USPS mailboxes.

Here is what you are allowed to send through these boxes:

  • Domestic mail, including Priority Mail Express, that weighs 10 ounces or less or is 0.5-inch thick or less
  • Domestic mail, including Priority Mail Express, with PC postage or metered postage
  • Domestic Priority Mail Express that is paid using a US Postal Service Corporate Account (USPSCA)
  • All types of Domestic Business Reply Mail

Priority Mail Express International and Priority Mail International that was prepared with:

    • Completed shipping label
    • Generated customs declaration form
    • Electronically-transmitted data
    • Paid postage online

International mail that is stamped or metered and meets all of the following:

    • Weighs 10 ounces or less
    • 0.5-inch in thickness or less
    • It does not require a customs declaration form

Priority Mail Express International items that weigh 16 ounces or less are paid using a US Postal Service Corporate Account (USPSCA). Online postage, postage meters, or information-based indicia should bear an electronically-generated PS Form 2976-B with data transmitted electronically to the USPS.

  • Pre-Paid Priority Mail Flat-Rate Envelope, with postage printed directly on the envelope
  • Official mail, except for mail requiring a customs-declaration form
  • Free Matter for the Blind – mail addressed to a blind person, with the words “Free Matter for the Blind” written on the envelope

Army Post Office (APO), Fleet Post Office (FPO), or Diplomatic Post Office (DPO) mail weighing 10 ounces or less, or 0.5-inch in thickness, bearing only postage stamps and should not require a customs form.

  • Priority Mail Express to APO/FPO/DPO should bear a PS Form 2976-B, regardless of the contents, weight, or value.

 APO/FPO/DPO mail paid with methods other than postage stamps, with a weight of fewer than 16 ounces, should not require a customs form.

  • Priority Mail Express to APO/FPO/DPO should bear a PS Form 2976-B, regardless of the contents, weight, or value.

A mail or package with online shipping labels may also be put in a USPS Drop Box as long as it meets the criteria for weight and thickness. It needs to have correct postage and labels affixed, and fees must be paid. It also needs to have a return address on the envelope.

If you have any mail or package that weighs more than 10 ounces or is more than 0.5-inch in thickness, you can still send it through the US Postal Service. All you need to do is go to your local post office and approach any retail service counter so that an employee may help you with your mail.

What Kind of Mail CAN’T You Put in Blue Mailboxes?

Not all mail can be dropped off in USPS mailboxes.

Here is the kind of mail that you cannot put in these boxes:

  • Domestic stamped mail, including Priority Mail Express, that weighs more than 10 ounces or is more than 0.5-inch in thickness.
  • Any international mail with a customs declaration form that was not filled out and submitted online.
  • Any international mail that requires a customs declaration but bears postage stamps.
  • International stamped or metered mail that has a weight of over 10 ounces or is more than 0.5-inch in thickness.
  • Priority Mail Express International items that do not have a PS Form 2976-B.
  • APO/FPO/DPO mail that weighs more than 10 ounces, or is more than 0.5-inch in thickness, and bearing only postage stamps as postage.

If you put any of the mail pieces above in a USPS Drop Boxes, they will not be sent to the recipient, and they will be on hold at your local post office, or they may be returned to you.

What Do Different Mailboxes Mean?

There are different mailboxes, and each one has a different intended purpose.

USPS Drop Boxes

These mailboxes are provided for everyone’s use as long as the mail they intend to send through these boxes meets the guidelines above. They are commonly found in populated cities but not in rural areas.

These mailboxes have a slot that is big enough for mail to be dropped off but small enough to prevent prying hands from stealing the contents.

Residential Curbside Mailboxes

These are the ones that first come to mind when you think about mailboxes.

These are mailboxes installed along the road. Each curbside mailbox is designated for one address only and normally has an incoming and outgoing mail receptacle.

Homeowners with these mailboxes can have mail delivered to their houses. They also have the option to send outgoing mail through these boxes.

All they need to do is place their outgoing mail in the proper receptacle and raise the carrier signal flag so that the mail carrier can pick it up on the next delivery.

Residential Wall-Mounted Mailboxes

These mailboxes are mounted directly to the wall, so they take up very little space.

They often have locks to keep the mail secure, as apartment buildings are notoriously prone to mail theft.

Most wall-mounted mailboxes are only limited-service, meaning they can only be used for incoming mail. However, you can have it as a full-service mailbox by contacting your local postmaster general.

Cluster Mailboxes

This type of mailbox is found in apartment buildings or condominiums.

They are located near the entrance or in the lobby so that it is accessible to the mail carrier.

Cluster mailboxes are characterized by one big unit of individual compartments, each with its own lock. The mail carrier usually has a master key that can open the back of the unit to collect outgoing mail.

Can Household Mailboxes Be Blue?

No rule dictates that household mailboxes have to be a certain color. Residential mailboxes can be any color.

They can even be blue.

No rule prohibits homeowners from painting their mailbox in any color, including blue, as there is no risk of confusing household mailboxes with USPS blue boxes.

The USPS is only strict with the carrier signal flag color, which must be easily visible to the mail carrier. The flag should not be green, blue, white, brown, or yellow.

Household mailboxes are much smaller than USPS blue boxes and are constructed differently, so they cannot be confused with USPS Drop Boxes, even if they are also blue. Plus, USPS blue boxes usually have the USPS logo on them.


What Is A Collection Box?

What Can And Cannot Be Deposited In A Collection Box?

USPS Color Requirements for Curbside Mailboxes: What You Should Know