Two-letter postal abbreviations: why "MP"?

According to all sources I consult, the North Mariana Islands, a U. S. territory, uses the 2-letter abbreviation MP. why? CA and AS and VI (even CZ, before the U. S. ceded the Canal Zone to Panama) are obvious, but not MP. where did it come from and what does “MP” stand for? :confused:

I’m guessing but Marianas Protectorate from it’s position as a UN protectorate under the US?

I’ll put a little more effort and try and find a cite.

MA and NM (the most obvious) were already taken. I would’ve said MR next, but that’s Mauritania…excuse me while I hunt up an atlas…

No, not “protectorate”, but UN Trusteeship – could the P stand for the “pacific” in the full title of the “Trust Territory of the Pacific Islands”?

They were the first to spin off from the Trusteeship, as a Puerto Rico-style US “commonwealth”, so Marianans are Americans now.

The other pieces of the Trusteeship became nominally independent nations, though in a monetary/postal/defense union with the USA so we DO have “domestic” postal codes for them: Federated States of Micronesia = FM (good) ; Marshall Islands = MH (ok, I suppose); Palau = PW (huh? “W”? Western district of the Pacific Trust Territory?).

BTW, galen: MAdagascar and MalawI also share their international 2-letter with a US state.