# Private mailbox

A private mailbox is a box rented at a commercial mail-receiving agency, written as a PMB or # number after that agency's own street address.

Date: 2026-09-10

A private mailbox — a PMB — is a box rented at a commercial mail-receiving agency rather than from the postal service, written as a `PMB` or `#` number after that agency's own street address. On paper it looks like a suite in an office building, because that is the form the postal service requires.

## What Spaw answers

`is_private_mailbox` is the flag and `address_type` reads `private_mailbox`. At +60 it is the heaviest of the four delivery-point weights, though not the heaviest weight in the address product: an address the deliverability check reports undeliverable carries +80.

The detection is the interesting part: it comes from the way the postal service requires such an address to be written, not from a licensed database of agencies. A `PMB 214` or a `# 214` after a street address is the tell, and it is a rule about spelling rather than a lookup.

## The limit that follows from that

A private mailbox written without its PMB number is indistinguishable from a suite. Where the licensed deliverability check would answer the question outright, this service does not run it — `is_cmra` stays null — so the flag catches the addresses that are written correctly and misses the ones that are not.

A PMB is not a lie. It is a mailing address, useful and legal, that says nothing about where anybody lives.

Reference: https://spaw.co/glossary/private-mailbox