*shrugs*

Like you guys said, Rowling said almost zero about countries besides the UK. Instead of the Ministry of Magic I gave the US the Department of Sorcery(so that the Secretary of Sorcery could be a secret part of the President's cabinet). My school was the New York Academy of the Magic Arts, and was also supposedly prestigious. Maybe they both exist and are something like rival schools. 

In my RP wizarding society existed literally underground, and could be reached through a secret entrance in the subway. Though I guess with muggles all knowing about magic, that's pretty unnecessary.