I'd like to write where someone is from, on a website with an international context. The objective is to balance style, brevity and correctness. I only need country-level resolution, so if someone is from Berlin, I plan on writing Germany, whereas if they're from Sydney, I plan on writing Australia.
I suspect that the USA should be an exception here, as I often heard people from the States feel very much associated with their state (I heard a lot more Chicago, Illinois than, say, Sydney, New South Wales).
Does this sound like a reasonable assumption? How should I write the state/country pair in this case? Illinois, United States? United States, Illinois? Something else altogether?
Edit: another small tidbit, the lion's share of the target audience is in the teenager/young adult age range.