Mailbox Policy for Maine’s State and State-aid Highways

Mailbox Policy

If you live on a state highway, the mailbox and other policies are outlined in this guide.

For convenience and practicality, mailbox installations have been allowed within the right-of-way of Maine’s state and state-aid highways; however it is important to recognize that such installations have two very important conditions:

  • The mailbox must be installed in accordance with applicable standards to ensure that mail can be delivered and that the mailbox does not create an obstacle or safety hazard to those that use or maintain the highway, and
  • The mailbox is installed entirely at the owner’s risk.  In other words, if the mailbox incurs damage during any sort of highway operations or maintenance, the property owner is not entitled to replacement or compensation.  In fact, if the mailbox was not installed in accordance with the applicable standards as stated above, the owner may even be held liable for injuries or damages that may have been incurred as a result.
  • Mailbox Policy Documents

Mailbox Installation Standards

General Location:

Whenever possible, place your mailbox after your driveway opening. This location improves its visibility, minimizes the amount of snow that comes off the plow, and improves the approach for your mail carrier.

Mailbox should be on the right side of your driveway, as you exit your driveway.

Figure a - Mailbox should be on the right side of your driveway, as you exit your driveway.

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Mailbox Height:

According to USPS standards, a mailbox must be installed so the bottom of the mailbox is between 41 inches and 45 inches above the highway shoulder. MaineDOT recommends the height be closer to the 45-inch measurement to minimize the chances of being struck by the plow truck wing (fig. f).

Figure f - Recommended Mailbox Height

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Mailbox Support Design:

In many cases, it is best to use an extended arm post with a free-swinging suspended mailbox (fig. b). This allows snowplows to sweep near or under the box without damage, and provides easy access for your mail carrier. Place a red reflector on the arm at the point closest to the road. This will help your local snowfighter see and avoid your mailbox during winter storms.

Offsets from Roads:

Mailboxes should be set back from the edge of the shoulder, regardless of whether the shoulder is gravel or paved. In other words, the face of the mailbox should be at least one foot back from the edge of the normally plowed surface of the highway or the face of curb (fig. b). Greater offset distances are encouraged so the mail carrier can move out of traffic and to minimize potential damage to your mailbox.

A mailbox in a sidewalk should leave at least 36 inches behind the back of the box or the post, whichever is located the furthest from the road (fig. b).

Figure b - Mailbox Support Design and Road Offset

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Post Size, Type, and Embedment:

Mailbox posts must be sturdy enough to hold up the mailbox in all types of weather. However, they can’t be so rugged that they present a hazard to vehicles that leave the road. If a mailbox support is struck by a vehicle, it must easily break away. Therefore, the following types of posts are recommended:

  • 4" x 4" wooden posts embedded two feet into the ground (fig. c). Larger wooden posts (4" x 6" or 6" x 6") may be used only if the post is drilled through with an appropriate spade bit to create a shear plane (fig. d).
  • One-inch to two-inch round diameter steel or aluminum pipe, or standard U-channel post embedded two feet into the ground (fig. e).

Unacceptable Mailbox Supports Include:

  • anything filled with concrete,
  • masonry and stone structures,
  • heavy steel structures, and
  • most objects that were intended for other uses (e.g., antique plows, I-beams, etc.).

Mailboxes, attachments or support systems not consistent with this policy are considered deadly fixed objects and are in violation of Maine law (23 MRSA  §1401-A). When MaineDOT sees this type of installation, the owner will be informed and immediate removal will be requested. If the property owner doesn’t comply with this request, MaineDOT may remove the installation and seek reimbursement from the property owner for all costs.

Figure c d e - Acceptable Mailbox Supports

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