Locking Post-Mount Mailbox - Large, Black, USPS Approved - Architectural Mailboxes

Locking Post-Mount Mailbox - Large Black Residential Mailbox with Concealed Compartment

The Mailsafe by Architectural Mailboxes is a large locking post-mount mailbox designed for homeowners who want curbside security without sacrificing style. Mail carriers deposit letters and flat envelopes through a top delivery slot - measuring 10 in. W x 1.75 in. H - where they drop safely into a hidden locked compartment below that only the owner can open. It is USPS approved, making it a fully compliant choice for standard residential curbside delivery. Fully assembled out of the box, this black mailbox requires no tools to set up and fits neatly on any Architectural Mailboxes post designated with the letter C.

SecurityLocking

USPS StatusApproved

Capacity1,450 cu. in.

Impact-Resistant, Rust-Free Build for Year-Round Outdoor Use

This secure mailbox is constructed from UV-protected polypropylene plastic, a weatherproof material that resists corrosion, fading, and moisture without ever needing paint or a protective coating. Unlike metal mailboxes that can rust or dent over time, this durable plastic build holds its shape and color through rain, snow, and intense sun exposure. The magnetic closure on the front door keeps it tightly shut against wind and rain, preventing water from entering the mail compartment. At 10 lb, the unit is sturdy enough for permanent curbside installation while remaining easy to handle during setup.

MaterialPlastic (Polypropylene)

ColorBlack

Product Weight10 lb

Concealed Locking Compartment with Outgoing Mail Flag - Secure Mailbox Feature

The standout security feature of this locking mailbox is its two-zone design: an open top slot for incoming carrier drops and a fully concealed lower compartment that only unlocks with the included keys. Mail carriers never need access to the locked zone, which means your letters, bills, and small packages stay protected from porch pirates and weather the moment they are delivered. Two keys are included with the mailbox. The built-in outgoing mail indicator - a red flag visible from the street - lets your mail carrier know to collect outgoing letters without you needing to flag them down separately.

Lock TypeConcealed Compartment Lock

Keys Included2 Keys

Outgoing MailFlag Indicator

Post-Mount Mailbox Installation - Dimensions and Post Compatibility

This post-mount mailbox arrives fully assembled with no tools required for setup - making it one of the easiest large locking mailboxes to install at the curb. It is designed to mount exclusively on Architectural Mailboxes posts that carry the letter C designation; mounting hardware is included with compatible posts, not with the mailbox itself. The T3-style box measures 9.53 in. H x 13.0 in. W x 21.62 in. D, placing it in the large mailbox category with a 1,450 cu. in. capacity suitable for busy households. Access is front-only, and the front door closes with a secure magnetic latch to keep it shut in windy or wet conditions. A 3-year manufacturer warranty backs the product.

Dimensions (H x W x D)9.53 x 13.0 x 21.62 in.

Mount TypePost Mount (Letter C Posts)

Warranty3 Year