USPS carriers do not open locked mailboxes and do not accept mailbox keys.Locks cannot be used on contemporary or traditional mailbox designs.

Slots must also be large enough to accommodate unfolded US Priority Envelopes.Locking mailbox slots must be large enough to hold the resident’s normal daily volume of mail.Protective flaps on locking mailboxes must be oriented inward so that mail carriers can place mail into the slot without additional effort.Slots for incoming mail must be at least 1.75 inches high by 10 inches wide.All Mail Boss curbside boxes are USPS approved. They must meet the same functional requirements as standard mailboxes and must be approved by the postmaster. Locking mailboxes effectively prevent theft of incoming mail. Newspaper receptacles may be mounted on the same post as the mailbox, but they must not contact it directly or be supported by it.Steel or aluminum pipes with a 2-inch diameter are also acceptable. Curbside mailbox posts should be buried less than 24 inches deep and made from wood no larger than 4 inches high by 4 inches wide.Mailboxes must be placed 6 to 8 inches away from the curb the incoming mail slot or door must be 41 to 45 inches from the ground.Numbers must be positioned visibly on the front or flag side of the box. The box or house number on a mailbox must be represented in numbers that are at least 1 inch tall.Curbside mailboxes must be placed on the right-hand side of the road and facing outward so that mail carriers can access it easily without leaving their vehicle.All manufactured mailboxes must meet the internal and external dimension requirements of the USPS.USPS mailbox regulations for in ground and surface mount post installation.

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