I'm fairly sure they grow in most corners of the world. For example, you missed Europe out where liberty caps, Psilocybe semilanceata, can often be found in sheep fields in autumn where they grow on the dead roots of grass. (I don't know why they seem to prefer sheep fields but from my experience, you have a better chance of finding them there).

They're great fun. If taken responsibly. (Know your limits / Plan your trip / have non-trippers in the party etc.)

Also, I'm fairly sure fly agarics don't contain psilocybin / psilocin. But they're still hallucinogenic and therefore magic mushrooms.