
The United States Postal Service, commonly known as USPS, has laws and regulations for residential mailboxes and mail delivery. The Domestic Mail Manual documents these in quite some detail.
Only a few people know about these rules and regulations. They are also not very easy to read. This is understandable because, if you are like me, then you will only consider these regulations and their implications when you have a problem of some sort.
Mailbox laws and regulations you shouldn’t ignore
Many thousands of people are cheated out of millions of dollars by mail scams and mail theft every year. So, it is important to understand the basic rules and policies that govern residential mailboxes.
When considering the purchase or relocation your mailbox then it is important to understand these laws especially based on the area where you live. If you understand the basic rules around the use of residential mailboxes then it will help you when dealing with neighbours, unsolicited mail, illegal mail delivery, and even mail theft.
You can learn about laws and regulations for residential mailboxes by reading the Domestic Mail Manual if you have a spare few hours and you are bored. On the other hand, if you don’t want to read pages of text governing the use of mailboxes, and let’s face it, who does, then the sections below will help you understand the most important points about mailbox and mail delivery rules.
Laws and regulations for types and size of residential mailboxes
Residential mailboxes and mail delivery requirements are specified in the USPS manual. There are many online retailers that supply regulation mailboxes. However, before you buy mailboxes in stores or online, make sure it is USPS approved.
Post mount mailboxes

Road-side or post mounted mailboxes are very popular in most states.
These types of boxes are available so that the USPS can deliver more quickly and easily. It is not because the mail persons are lazy and don’t want to get out of their delivery trucks!
Curbside mailboxes are available in three sizes: –
- Small T1 (C1) size is approximately 5 inches wide by 6 inches tall and 18 ½ inches long.
- Medium T2 (C2) size is approximately 6 inches wide by 7 inches tall by 19 inches long.
- Large T3 (C3) size is approximately 8 inches wide by 11 ½ inches tall by 22 ½ inches long.
The “T” stands for Traditional and the “C” stands for Contemporary. The dimensions reflect the minimum interior size.
Posts for roadside mailboxes
Post mount boxes should be:
- positioned 6 to 8 inches from the curb
- approximately 41 to 45 inches high measured from the lawn to the top of the installed mailbox, not the top of the post.
This is clearly shown in the image below:

If the post has a vertical arm, the arm should not extend any closer than 6 inches from the curb.

When installing your new set, make sure your set complies with these regulations. It should be set at least 24 inches below the ground to ensure everyone’s safety.
Be cautious when building your own mailbox and post. Mailbox collisions account for up to 100 motorists deaths every year.
Some posts are mounted in concrete or constructed of indestructible materials. So a collision with a motor vehicle can severely damage the vehicle and injure its occupants.
Wall mount mailboxes

The U.S. Postal Service does not govern wall mount boxes; however, you should notify your local mail carrier before installation to ensure proper placement of the mailbox and check for any local codes or regulations governing placement of the box.
The product should operate easily, and nothing should obstruct the opening and closing of the lid.
TIP: Also check with your homeowner’s association to see if they have any association by-laws which you need to comply with.
Who really owns your mailbox?
As a homeowner or purchaser of the mailbox, whether post-mounted or wall-mounted, you technically own the mailbox. After all, you paid for it! You maintain it. However, USPS ultimately controls the usage of the residential mailboxes. This does seem unreasonable but it is part of the current mailbox regulations.
That means that any tampering of the mailbox is a federal offense!
What items can be delivered to the mailbox?
The USPS Domestic Mail Manual states:
“no part of a mail receptacle may be used to deliver any matter not bearing postage, including items of matter placed upon, supported by, attached to, hung from, or inserted into a mail receptacle.
Domestic Mail Manual
In other words, the mailbox may not be used for anything other than for pieces of mail with postage attached.
The USPS Domestic Mail Manual goes on to states that it is a federal offense and there is a significant penalty for violating this law.
Who can deliver mail?
Existing residential mailbox laws state that only authorized letter carriers may insert mail into a residential mailbox. A penalty will be imposed for anyone who is not a letter carrier and is inserting mail in the residential mailbox. It is a federal offense for tampering with the mail and a fine or possibly jail time can be the punishment for the offense. Generally, residential mailboxes are for mail use only.
If the homeowner removes the newspapers and magazines then, in some localities, they may be left in the mailboxes. But it is always best to check with the local postmaster on this.
Mailbox Attachements
The USPS code states that private carriers may deliver newspapers and place them in the newspaper receptacle only. Wall-mounted mailboxes are more likely to have newspaper receptacles rather than post mounted mailboxes.
The receptacle cannot touch the residential mailbox, cannot interfere with the delivery of the mail, does not extend beyond the front of the mailbox and does not display any advertising except for the name of the publication.
There are many other mailbox accessories such as numbers, magnetic covers, flags, etc. Most of these are fine as long as they don’t interfere with mail deliveries.
It should noted that mailbox numbers must be 1″ tall and clearly visible.
Mailbox laws and regulations – conclusion
In summary:
- USPS has laws and regulations for residential mailboxes, which you may read in all the spare time you probably have!
- If you don’t want to bear the wrath of mail delivery personnel and local postmasters, then know the rules and regulations for post-mount and wall-mounted mailboxes.
- Only you and the USPS can legitimately access your own mailbox.
- Be careful when altering standard mailboxes.
- See choosing a residential mailbox for tips and ideas on how to select or enhance residential mailboxes.
- If in doubt about any of the above, contact your local postmaster.
- See residential mailboxes frequently asked questions.