U.S. Mail Supply Categories

USPS Approved Mailboxes - Commercial, Apartment, & Residential Units

All new construction and renovation designs REQUIRE U.S. Postal Service STD-4C compliant mailbox systems. Your options for USPS approved indoor & outdoor mailbox systems:

USPS Approved Cluster Mailbox Units Cluster Mailboxes
USPS Approved Indoor 4C Horizontal Mailboxes 4C Horizontal Mailboxes
USPS Approved Indoor 4B+ Horizontal Mailboxes 4B+ Horizontal Mailboxes
USPS Approved Indoor Wall Mounted Vertical Mailboxes Vertical Mailboxes
USPS Approved Residential Locking Pedestal Mailboxes Locking Residential Pedestal Mailboxes
USPS Approved Pedestal Mounted Mail Package Drop Box Mail Package Drop
USPS Approved Letter Drop Boxes for Sale Letter Drop Boxes
USPS Approved Delivery Package Vault Outdoor Mailbox Delivery Vault Drop Box
Commercial Mailboxes for USPS Delivery Commercial Mailboxes for USPS Delivery

USPS Approved Commercial Cluster Mailbox Units

USPS Approved 4 Door Cluster Mailbox 4 door cluster mailbox
USPS Approved 8 Door Cluster Mailbox 8 door cluster mailbox
USPS Approved 12 Door Cluster Mailbox 12 door cluster mailbox
USPS Approved 13 Door Cluster Mailbox 13 door cluster mailbox
USPS Approved 16 Door Cluster Mailbox 16 door cluster mailbox

How to Get a USPS Approved Mailbox

USPS Approved Mailboxes for Sale

As of October 5, 2006 all new construction and renovation designs REQUIRE U.S. Postal Service STD-4C compliant mailbox systems.


If your existing commercial mailbox meets USPS specifications, you can have it approved by your local postmaster. We carry new USPS approved STD-4C mailboxes for new buildings or businesses who are renovating. USPS approved mailboxes from U.S. Mail Supply are available in a variety of styles.


Buying a new mailbox might seem easy, however, there are regulations enforced by the United States Postal Service regarding mailbox specifications. Many postal customers aren’t aware of these regulations, then become confused when their mailbox isn’t approved. 


More information on STD-4C specifications can be found here: USPS Approved Mailbox STD-4C Regulations


The USPS has to regulate the types and styles of mailboxes allowed for residential and commercial use to prevent delays and accidents when delivering the mail. US Mail Supply offers a wide variety of USPS-approved mailboxes for homes and businesses. Residential and commercial mailboxes must meet specific USPS requirements, including box size, location, mail slot dimensions (when applicable) and identification information.


Depending on where you live, some of these restrictions and rules may not apply. To find out exactly what is and isn’t approved for use by the USPS, contact your local post office for clarification or visit the official USPS homepage.


Getting a USPS approved STD-4C mailbox from U.S. Mail Supply is easy. Fill out our 4C quote form to get started.

USPS Approved STD-4C Mailbox Quote Form

Frequently asked questions about USPS approval & mailboxes for USPS delivery

Question: How do I get USPS approval?
Answer: Either purchase a mailbox pre-approved for USPS delivery or view mailboxes with USPS delivery options and contact your local postmaster for the last word. Depending on where you live, restrictions like box size, location, dimensions and identification info might not apply. Give us a call if you have any questions.

Question: I am looking for commercial mailboxes pre-approved by the USPS.
Answer: Check out our commercial mailboxes for USPS delivery.

Question: Where do I find USPS approved mailboxes for apartments?
Answer: Many of our outdoor pedestal cluster box units and indoor 4C recess wall mounted mailboxes are USPS approved by default. Shop apartment mailboxes and view product specifications to find out if you need approval from your local postmaster.

Question: Are vertical mailboxes USPS approved?
Answer: In some cases, yes, but you will need verification from your local postmaster to know for sure. Take a look at our 3500 series 4B+ vertical mailboxes.

Question: Who is the manufacturer of USPS approved mailboxes from US Mail Supply?
Answer: Our mailboxes are manufactured by Florence Corporation.

Question: What are the USPS approved mailbox sizes?
Answer: All mailboxes for USPS delivery are held to STD-4C requirements. Learn more about STD-4C regulations for USPS approved mailbox units.

View all of the most common questions concerning ordering and installing mailboxes from US Mail Supply.

USPS Mailbox Regulations for Multi Family Residences

USPS mailbox regulations state cluster mailboxes installed in all new construction and major renovations of multifamily buildings must meet STD-4C specifications. New specifications dictate minimum compartment size, parcel locker ratio, standardized tenant design, ADA compliance and more. US Mail Supply is here to help you find the right 4C mailboxes for your building. 

Shop all apartment mailboxes for sale from U.S. Mail Supply.

Residential Post Mailboxes

Residential USPS Approved Mail Boxresidential mailbox on a curbside post must meet certain distance restrictions. All mailboxes must be 41” to 45” above ground level for easy delivery by foot or vehicle. The post must be 6” to 8” from the curb to avoid being a hazard for drivers or pedestrians. The posts themselves can be made of wood, steel, or aluminum. A post should go no deeper than 24” into the ground.

These mailboxes can be either traditional, contemporary, or locking. Both traditional and contemporary mailboxes can be made in three different sizes, depending on your needs. The approved sizes reach up to 22.8” x 11” x 15”. Locking mailboxes are allowed more size dimensions due to their security features, though it is always recommended to check with your local post master before installing your own locking mailbox.

Indoor mailboxes can be horizontal, vertical, or custom made to meet your facility needs. All indoor mailboxes have available locks and keys to protect your correspondence and prevent identity theft. US Mail Supply even has USPS-approved drop boxes for safe package and parcel delivery.

Buying and installing the right mailbox for your home or business is easy with US Mail Supply. All our mailboxes are made to USPS specifications and include easy to follow installation instructions to help ensure you meet all official guidelines.

Wall Mounted Residential Mailboxes

Before installing a wall mounted mailbox to your home, you must check with your local post office to determine the height and position for approval. Postal carriers must be able to easily reach your mailbox from the sidewalk, your front steps or porch.

If you choose a mailbox with a lock, only your incoming mail will be secure as USPS workers are not allowed to take your mailbox key. This can limit the size of parcels you will be able to receive based on your mail slot size.

Neighborhood Delivery & Collection Box Units and Cluster Mailboxes

Cluster mailboxes and neighborhood delivery and collection box units (NDCBU’s) make for easy delivery to multiple residences at once. Since NDCBU’s were transitioned out in favor of cluster boxes, there are more rules about their use by the USPS. New NDCBU’s cannot be purchased or installed unless it is to replace an existing or damaged unit.

Cluster mailboxes from US Mail Supply are USPS approved and include a host of security features. Compartments are reinforced, weather resistant and accommodate larger parcels than the previous NDCBU’s. Please note, your local post office must be consulted before installation due to specific placement rules.

Contact US Mail Supply for more information on USPS approved mailboxes.
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