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Shop Horizontal Mailboxes

For many years, horizontal mailboxes have been the standard for large multifamily residential and commercial mail delivery applications. They are now only available for replacements in buildings with USPS mail delivery. The best applications for horizontal mailboxes include delivery in university dorms, internal business offices and several other private applications. 

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USPS Mailboxes

Subject to local regulations and installation requirements, our products can comply with USPS standards, as defined by the Postmaster General.

Please note that the USPS periodically updates mailbox standards and guidelines. Before proceeding with mailbox projects, we recommend you consult with your local Postmaster to comply with your specific area guidelines. US Mail Supply experts are standing by to help you navigate the product selection and installation process.

U.S. Mail Supply provides horizontal mailboxes for USPS and private delivery depending on your configuration and individual needs. Choose from our base models or build your own custom horizontal mailbox system.

USPS Approved Recess Mounted Horizontal Mailboxes

For USPS approved horizontal mailboxes, shop 4C recess mounted models.

4C front loading horizontal mailboxes are USPS approved by default for apartments, commercial buildings, or other multifamily residences. STD-4C compliance is REQUIRED for all new construction.

Shop USPS approved 4C mailboxes

…or use our custom 4C mailbox form and let us know exactly what you need.

USPS Approved and Private Use Horizontal Mailboxes

US Mail Supply offers our customers a wide selection of high quality indoor horizontal mounted mailboxes. With front and rear loading options available, these mailboxes are perfect for a wide variety of applications, including:Horizontal Mailboxes

  • Offices
  • Apartment Complexes
  • Military and Government Facilities
  • Schools
  • Universities
  • Private and Corporate Mail Centers

Made of high-quality materials, the 1400 Series is USPS approved for replacement purposes. The rest of the models are for private use.

Shop Apartment Mailbox Options from U.S. Mail Supply

If you’re shopping around for mailboxes for a multi-family or multi-unit building, consider all of our apartment mailboxes for sale online. We’ve got indoor and outdoor mailboxes for all sorts of multi-tenant apartment and condo complexes.

Convenient Mailroom SolutionsMailroom Organizational Supplies

US Mail Supply offers solutions to all your mailroom problems. From organization materials to cell phone cabinets, our professionals will help determine which products will best suit your home or facility requirements. We offer the widest selection of USPS approved mailboxes and private use boxes.

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