Mailbox Installation Rules: What the Post Office Requires Before You Install

Written by MJ, sculptor at Seaside MailboxUpdated Oct 26, 20263 min read

USPS mailbox positioning and height requirements and guidelines

In this article

1. Height: 41 to 45 inches
2. Setback: 6 to 8 inches from the curb
3. Custom mailboxes need your local postmaster's OK
4. Contact your Post Office before you install
5. Check road and county rules too
6. Mark your house number
Quick checklist
Sources

Yes, you can have a custom mailbox. The Postal Service allows custom-built curbside mailboxes, as long as they follow a few basic rules. Here's what they are, in plain English.

This is general guidance, not legal advice. Your local Post Office has the final word for your address.

1. Height: 41 to 45 inches

USPS asks that curbside mailboxes sit 41 to 45 inches from the road surface to the bottom of the mailbox or the point where mail goes in. That's the height a carrier can reach from the vehicle window.

White USPS mail truck driving down a residential street — Carriers deliver from the vehicle window, which is why the 41 to 45 inch height matters. Photo: Garrett Goolsby / Unsplash

2. Setback: 6 to 8 inches from the curb

The mailbox door should sit 6 to 8 inches back from the front face of the curb or the edge of the road. Close enough to reach, far enough not to get clipped.

Diagram of curbside mailbox installation: 41 to 45 inches from road surface to mailbox bottom, 6 to 8 inches from curb to mailbox door — The two numbers to remember: 41 to 45 inches up, 6 to 8 inches back.

3. Custom mailboxes need your local postmaster's OK

USPS says a custom-built curbside mailbox can be used if your local postmaster approves it first, and it should generally match approved manufactured mailboxes for flag, size, strength and build quality. In practice, that means a real, working mailbox with a flag, built solidly.

Close-up of bronze U.S. Mail box and carved address sign on owl mailbox sculpture — Every sculpture is built around a real, working mailbox.

Our sculptures are built around a working mailbox with a flag, to USPS standards. Before you install, a quick call or visit to your local Post Office is the easiest way to confirm everything for your address.

4. Contact your Post Office before you install

Road and curb conditions vary, so USPS recommends contacting your local Post Office before you put up or replace a mailbox. It's a short conversation and it saves headaches later.

Post office building in Seaside, Florida — A quick stop at your local Post Office, like this one in Seaside, Florida, saves headaches later. Photo: Kate Damaska / Unsplash

5. Check road and county rules too

Mail rules come from USPS, but the ground your mailbox sits on may belong to your city, county or the state. If your mailbox sits along a state highway, Florida's transportation department has its own safety rules for mailbox supports, so check with your county before you install.

Row of mailboxes on posts beside a winding country road — The strip of land your mailbox sits on may belong to the city, county or state. Photo: Damian Kamp / Unsplash

6. Mark your house number

Make your address easy to read from the street. We can carve or paint your house number right into the sculpture, so it's part of the design instead of a sticker on the side.