There are many examples; k12.<state>.us is another.
It is (or was for a long time, IDK) a strongly recommended practice from ICANN. I imagine nearly all countries to do that.
Except nobody uses the .us tld, but pretty much every every Japanese company is on a .co.jp
It is (or was for a long time, IDK) a strongly recommended practice from ICANN. I imagine nearly all countries to do that.