Abstract: A curbside mailbox wherein the outgoing mail compartment is located under the incoming mail compartment behind a single carrier service door. The incoming mail, when inserted, drops behind the outgoing mail compartment and falls into a deep mail storage area, to be retrieved by the owner through a locking rear access door. The rear access door retains a mechanical key lock and acts like a hasp fitting over a flange that is built into a upper rear wall. This feature allows the owner to double lock for added security or single lock placing a combination lock on the flange if the owner desires not to carry a key or give access to key for someone authorized to remove mail. The locking mailbox further includes a channel on top for a highly visible address display, a mounting channel on lower front to allow for quick and easy engagement, and a post cover assembly for safe and attractive installation.