According to an answer given here "It is illegal for anyone other than the USPS to put mail in someone's mailbox" From https://about.usps.com/news/state-releases/tx/2010/tx_2010_0909.htm

By law, a mailbox is intended only for receipt of postage-paid U.S. Mail.

This sure is a strange law. Why was it made? So it's illegal for someone to deliver their own mail in the US? What about non-mail items, like locking the door and putting the key through the mail slot, is this technically illegal in the US?

  • I'm voting to close this question as off-topic because there is no legal question here; from the referenced article the la is clear and unambiguous. Why a law is the law is a political/social question, not a legal one.
    – Dale M
    Feb 2 '16 at 7:22
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    The question in the title is asking whether it is really illegal. It is. The referenced article doesn't cite any sources, and government agencies have a tendency to overstate the law to their own benefit.
    – Tom
    Feb 2 '16 at 7:49
  • @DaleM where does it say that asking about the history of a law or why it was made is off topic for this site?
    – Guy McG
    Feb 2 '16 at 8:03
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    I vote to leave open on grounds that intent and public policy concerns are integral to the study of law.
    – Pat W.
    Feb 2 '16 at 11:51
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    Why a law is a law is a jurisprudential question and totally in the scope of this stack.
    – jqning
    Feb 2 '16 at 13:42

A mail slot is not a mailbox. So putting a key through a mail slot after locking the door is not the same as putting the key in a mailbox.


It is illegal to use a mailbox, yes. (Not necessarily a mail slot). You are looking for 18 USC 1725.

Whoever knowingly and willfully deposits any mailable matter such as statements of accounts, circulars, sale bills, or other like matter, on which no postage has been paid, in any letter box established, approved, or accepted by the Postal Service for the receipt or delivery of mail matter on any mail route with intent to avoid payment of lawful postage thereon, shall for each such offense be fined under this title.


As to why the monopoly exists, that's a legislative history question. There are all of the obvious advantages and disadvantages: network effects, interference with official mail, government income, freedom from spam; inconvenience, making it easier to receive unofficial mail, increased competition in mail delivery, no need for a second mailbox for newspapers, better advertising information from said spam.

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    What if you put a stamp on it first? Then you've paid postage. No?
    – Patrick87
    Feb 2 '16 at 16:16
  • Yes, that would likely cover this law. My guess is there's a law somewhere about "interference with the postal system" they could try to go after you on, but maybe not.
    – Tom
    Feb 2 '16 at 16:31
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    Yes you can put a stamp on it, but you'd need to cancel the stamps with a postmark and ensure they can't be reused. If you're doing this routinely or in bulk, you need an agreement with the USPS as well. The details are in the truly inspirational reading material that is Publication 542 - Understanding the Private Express Statutes. Feb 3 '16 at 8:21
  • The question concerns a mail slot while the law concerns mailboxes. The answer is no.
    – phoog
    Feb 3 '16 at 19:15
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    @Patrick87 Then you've paid postage, and the economic question arises about why you still self-deliver instead of having the post office do that for you, since you're paying for the service. Given the way the statue is written though, it's an open question if a penny stamp would avoid the "no postage" requirement. Pub 542 might have the answer (its introduction indicates the answer is no).
    – WBT
    Feb 4 '16 at 0:55

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