I actually wrote to them once. Got a reply, even, addressing me by name.
What do you think would be the fewest characters you could put on an envelope and have a reasonable chance of it being delivered to the correct person? Maybe “Cher” or “Mr T”? For organizations, “FBI” or “TI” would get to the correct place, right?
If you believe Cliff Stoll’s The Cuckoo’s Egg, CIA agents’ mailing addresses look like this:
That’s possible because that ZIP code is used only by the CIA. So if the internal mailroom is cool with you not using any other identifier, the USPS doesn’t care.
A Zip+4 identifies a single large building in an urban area or a block on one side of the street in a residential neighborhood or a similar small range of destinations.
Given that You should be able to get it down to a small set of information, such as house no. and Zip+4.
I grew up in such a place. When Zip Codes appeared, “name code” was enough.
The PENTAGON is so HUGE that it has its OWN zip code, area code and Subway sandwich shop:p:p:p:p:p