Locking Mailbox with Optional Combination Lock or Key Lock

tl;dr: Adding a lock yourself may not be legal, but you can buy a USPS-approved mailbox with a lock The box will need a mail slot or similar,

The steel mailbox features a locking hinged door for security It features a top slot that measures 10 1 2 x 3 4 Mailbox is wall

mailbox with slot and lock Shop for Locking Mailboxes in Mailboxes and Mailbox Accessories Buy products such as Barska Locking Wall Mount Mailbox at Walmart and save

mailbox slot in wall Buy Barska Locking Wall Mount Mailbox featuring Protects Mail, Ballots, Slips and More, Spring-Loaded Drop Slot Door, Dimensions: x