Accessibility Installation References

A key consideration for any project is designing appropriate accessibility, and how the mailboxes are installed into that project is no exception. All wall mounted mailboxes which will be serviced by the U.S. Postal Service (USPS) must also be installed according to specifications as outlined in the USPS STD-4C regulation. Here are some quick references related to accessible uses and USPS requirements to help you in determining your project design and layout.

Meeting USPS Installation Requirements

Approved 4C mailbox products from National Mailboxes are designed to adhere to STD-4C regulations. To ensure your project complies with USPS regulations for wall-mounted mailboxes, your mailbox center must be installed according to the following U. S. Postal Service guidelines.

4C ADA Installation HeightsInstallation requirements specified in the U.S. Postal Service STD-4C regulation:

  • At least one customer compartment shall be positioned less than 48 inches from the finished floor
  • No parcel locker compartment (interior bottom shelf) shall be positioned less than 15 inches from the finished floor
  • No tenant lock shall be located more than 67 inches above the finished floor
  • No customer compartment (interior bottom shelf) shall be positioned less than 28 inches above the finished floor
  • The USPS Arrow lock shall be located between 36 and 48 inches above the finished floor
Standards Governing the Design of Wall-Mounted Centralized Mail Receptacles. Federal Register/Vol. 69, No 171/September 3, 2004.  Rules and Regulations POSTAL SERVICE, 39 CFR Part 111.

Meeting ADA Installation Requirements

ADA Front ReachADA Side ReachAccessibility regulations may vary by type of facility and by governing jurisdictions. Therefore, always consult local building officials and codes for applicable accessibility requirements that could affect your mailbox project. Below are industry references for your convenience.

2010 ADA Standards for Accessible Design, Department of Justice Code of Federal Regulations, ADA CHAPTER 2: SCOPING REQUIREMENTS, 228.2 Mail Boxes: Where mail boxes are provided in an interior location, at least 5 percent, but no fewer than one, of each type shall comply with 309. In residential facilities, where mail boxes are provided for each residential dwelling unit, mail boxes complying with 309 shall be provided for each residential dwelling unit required to provide mobility features complying with 809.2 through 809.4. The full text can be found at:


Additional Information:

4C Horizontal Mailboxes – USPS Approved and STD-4C Compliant
Choosing Centralized Mailboxes that Comply with the US Postal Service Regulations
Shop all Commercial Mailboxes from National Mailboxes