Four. I spent about an hour in the wikkypeeja hole and then decided Wikipedia is useless and started tearing through some data files that I had laying around from a GIS project from 2015.
The 47,329 citizens the Northern Mariana Islands and the 168,801 citizens of Guam are US citizens, though. They're all UTC+10, which is, per the Census department's ZCTA data, the easternmost US timezone. The absolute easternmost zip code is in Tinian (96952, at 15°0′0″N, 145°38′0″E), which also has the distinction of being the place where Little Boy was loaded into the Enola Gay. Apparently, various companies keep trying to build hotels and casinos but it falls through every time, due to financial troubles, allegations of money laundering, etc.: https://en.wikipedia.org/wiki/Tinian (photos are from there). The air and naval bases remain.
@p love you pete, made sure to make a post thanking you and im thanking you now, thank you for being here friend without you i would probably have offed myself long ago. thank you for everything you do for me and fediverse and other places
@p Doing well, thank you! I'm still in grandma heaven with the new grandbaby, I can't come here as much as I would like to. PS-Thank you for still keeping this place up and running, I still love it. Hope all is well on your side. 🥰🌼
@thedonnerd HAPPY NEW YEAR THEDONNERD!! LONG TIME NO SEE (but I have been in a hole kinda so probably just me not noticing, like a jerk) HOW ARE YOU DOING