I think Greenland is part of Denmark.

Don’t forget administrative districts, like Guam, or Puerto Rico.

Tokyo has a “grid-based” street addressing system, that I never fully understood. There are streets with no name, there (wasn’t that a U2 song?).

I find that long/lat (don’t forget the Southern Hemisphere) is about the only universal constant. If I am writing software that has a focus on just one nation, that helps a lot, but I need to keep in mind, that I may want to expand it.

Normalizing time, across the International Date Line, or Prime Meridian, is also fun (Daylight Savings makes this fun. India has a time zone that has a 30-minute component).

No, this is not the equivalent question. The more appropriate one for US is Puerto Rico or even US Virgin Islands.

As in the article, I think it depends to some extent on what question you're asking. "What is the population of the US?" is almost definitely intended to include Alaska and Hawaii, but if someone asks "what is the geographic center of the US," they probably intend for the answer to be something in South Dakota, not the point off the coast of British Columbia that you get if you include Alaska and Hawaii, or the point out in the middle of the Pacific if you include Guam, etc.

Politically they are two of fifty states of the United States, and on an equal footing with the other 48.

Geographically, Alaska is part of North America, and Hawaii isn't.

A discussion of all the various territories of the US

https://www.youtube.com/watch?v=ASSOQDQvVLU