The U.S. Postal Service uses four USPS delivery modes to get mail to your address: door, curbside, centralized, and rural. Which one applies to you depends on when your neighborhood was built, how densely populated it is, and what kind of property you live in. The Postal Operations Manual sets the rules for each, and they determine where your mailbox sits, who owns and maintains it, and what you’re expected to do as the recipient.
Door Delivery
Door delivery is what it sounds like: a carrier walks up to your home or business and drops mail through a slot or into a box mounted at or near the front entrance. It’s covered in Section 631.23 of the Postal Operations Manual.1United States Postal Service. Postal Operations Manual – 631 Modes of Delivery
If your carrier walks up to your door, you almost certainly live in an older neighborhood where this service was established long ago. USPS treats door delivery as a legacy arrangement. The agency does not approve it for new construction and only maintains it at addresses where it already exists. These routes are grandfathered, meaning the service continues unless the homeowner asks for a change or USPS determines a shift is necessary. New residential developments will not get door delivery.
Curbside Delivery
Curbside delivery is the setup most suburban homeowners recognize: a carrier drives the route and reaches each mailbox from the vehicle without stepping out. It’s addressed in Section 631.21 of the Postal Operations Manual.1United States Postal Service. Postal Operations Manual – 631 Modes of Delivery If you have this mode, the mailbox is yours to install and maintain, and USPS has specific rules about how it must be built and placed.
Height and Setback
The bottom of the box, or the mail entry point on locked designs, should sit 41 to 45 inches above the road surface. The box must also be set back 6 to 8 inches from the front face of the curb or the edge of the road.2United States Postal Service. US Postal Service Standard Mailboxes, Curbside These measurements let the carrier reach the box safely from the driver’s seat. If your box drifts out of spec because the post has shifted or the road has been repaved, fixing it is on you.
The house number must appear on the box in numerals at least one inch high in a color that contrasts with the box. If your mailbox is on a different street from your house, both the street name and house number need to show on the side the carrier approaches.3United States Postal Service. Requirements for City Delivery Mail Receptacles
Approved Boxes and Posts
Curbside mailboxes must carry a “U.S. MAIL” inscription and an “Approved By The Postmaster General” marking on the carrier service door.2United States Postal Service. US Postal Service Standard Mailboxes, Curbside Approved models are listed in the Postal Bulletin and stocked at most hardware stores.
The support post matters too. The Federal Highway Administration recommends a 4-by-4-inch wooden post or a 2-inch-diameter steel or aluminum pipe, buried no more than 24 inches deep, so it will bend or break away if a vehicle hits it. Heavy metal pipes, concrete columns, and other rigid supports create a hazard and can expose the property owner to liability.4United States Postal Service. How to Install a Mailbox Before installing or replacing a box, contact your local post office.
Centralized Delivery
Centralized delivery is now the default for essentially all new residential and commercial construction. Instead of a box at every home, USPS requires grouped mailbox units that let one carrier serve dozens of addresses at a single stop. Section 631.2 of the Postal Operations Manual makes this explicit: curbside, sidewalk, and door modes are generally not available for new delivery points, with rare case-by-case exceptions.5United States Postal Service. POM Revision – Modes of Delivery
Cluster Box Units
The most common piece of centralized equipment is the cluster box unit, a freestanding pedestal with individual locked compartments and integrated parcel lockers for larger items. The carrier opens a master loading door and fills every compartment at once. Each resident gets a key to their own compartment. When a package arrives, the carrier leaves a one-time-use key in your box that opens a parcel locker.
Keys and Lock Replacement
If USPS owns the cluster box, you receive a compartment lock and three keys at no charge when you move in. Lose all your keys and USPS will install a new lock and issue new keys at your expense.6United States Postal Service. What is a Cluster Box? What is a Parcel Locker? If a landlord, HOA, or property management company owns the cluster box, that organization handles all lock and key issues. Carriers are generally prohibited from accepting keys for locks on privately owned receptacles.
Rural Delivery
Rural routes cover larger areas with fewer addresses per mile, and carriers work from vehicles, approaching mailboxes along the line of travel on public roads. Rural delivery is not tied to a single Postal Operations Manual section the way the city modes are; route-specific standards appear in Section 653 of the manual.
Rural mailboxes meet the same Postmaster General approval standards as curbside boxes and follow the same 41-to-45-inch height and 6-to-8-inch setback rules.2United States Postal Service. US Postal Service Standard Mailboxes, Curbside Currently approved box dimensions run roughly 18.5 to 22.8 inches long, 6.25 to 11 inches wide, and 6 to 15 inches high.7United States Postal Service. Curbside Mailboxes – A Chronology of Size Changes
The Signal Flag
The flag on the side of a rural mailbox has a real job. Raising it tells the carrier you have outgoing mail to pick up. Without the flag up, the carrier may drive past if there is nothing to deliver that day. A mailbox sold without a flag is classified as “limited service,” and USPS requires a warning label explaining that carriers won’t stop when there is no mail to deliver.8United States Postal Service. US Postal Service Standard Mailboxes, Curbside The flag can be almost any color except green, brown, white, yellow, or blue. Fluorescent orange is preferred.
Keeping the Approach Clear
Rural residents have to keep the path to the box safe. That includes clearing snow, ice, and debris. If the carrier can’t reach the box safely, delivery may be delayed or skipped for the day, with mail attempted again the next delivery day.9United States Postal Service. Keep Letter Carriers Safe for Mail Delivery; Clear Snow, Ice from Mailboxes, Sidewalks The same idea applies to suburban curbside boxes: parked cars, trash cans, or snow piled around the box can cost you a day’s delivery.
Who Owns and Maintains Your Mailbox
USPS does not maintain personal mailboxes. If you own the freestanding curbside or rural box at your address, repairs and replacement are your responsibility. If the equipment belongs to USPS, such as a USPS-installed cluster box, report damage to your local post office.10United States Postal Service. Mailboxes – The Basics
Privately owned cluster boxes in apartment complexes, condos, and HOA communities are the responsibility of the property manager or association. If you don’t know who owns your cluster box, ask your local post office. If they don’t service it, your landlord or management company does.
Requesting a Different Delivery Mode
Switching modes is hard, and for most people the answer is no. The hardship provisions in Section 631.5 of the Postal Operations Manual are the main path for an individual resident to request a change. The most common approved reason is a medical condition that keeps someone from reaching a cluster box or curbside mailbox. USPS will require a letter from a physician describing the limitation and stating whether it is temporary or permanent.
Start with your local postmaster, who reviews whether the change is feasible given the route’s safety and operational constraints. If the postmaster denies the request, you can escalate through the Postal Service’s District Consumer and Industry Affairs offices, which handle local service disputes.11Postal Regulatory Commission. Consumer Assistance Approvals rest on humanitarian criteria, not convenience. Preferring door delivery over a short walk to the cluster box won’t clear that bar.
Federal Protections for Your Mailbox
Your mailbox is on your property, but it’s part of the federal mail system, and federal law protects it no matter which delivery mode serves you.
Damaging, destroying, or breaking open a mailbox is a federal crime under 18 U.S.C. 1705, punishable by up to three years in prison, a fine, or both.12Office of the Law Revision Counsel. 18 US Code 1705 – Destruction of Letter Boxes or Mail Stealing mail is a separate and more serious offense under 18 U.S.C. 1708, carrying up to five years.13Office of the Law Revision Counsel. 18 US Code 1708 – Theft or Receipt of Stolen Mail Matter Generally
It is also illegal for anyone other than a postal carrier to place unstamped items in a mailbox. Flyers, business cards, menus, and neighborhood notices all fall under this rule, and each occurrence is a finable offense.14Office of the Law Revision Counsel. 18 USC 1725 – Postage Unpaid on Deposited Mail Matter Unstamped material found in a mailbox is technically subject to the postage that would have applied if it had been mailed.15United States Postal Service. Restrictions for Attaching Flyers, Posters, etc. to a Mailbox The rule covers every part of the receptacle, including the flag and the post. One exception: door mail slots are not regulated by USPS, so a flyer left in a door slot does not run afoul of federal law.