Anvilania is a small country, so small that it needs to be viewed through a magnifying glass on a map. The country itself borders Dunlikus and is in the shape of an anvil. Its exports, imports and general business is, unsurprisingly, anvils. The national anthem consists of Perry Como singing the word 'Anvilania' three times in a drowsy tone, putting almost everyone who hears it to sleep.
Yakko becomes King of Anvilania because he is the last remaining member of the royal family, through a rather complicated family tree. The people of the medieval kingdom are happy to see him, including the Prime Minister (Hello Nurse), and welcome him by playing their anvils like metallophones.
Unfortunately, on the first day of Yakko's reign, the dictator of neighboring Dunlikus attempts to claim Anvilania for himself, ultimately declaring war on Yakko. After frightening his army off by being too truthful, Yakko and his siblings defeat the dictator themselves with a Trojan anvil, Perry Como, and a lot of anvils. During the victory celebration, the hitting of the musical anvils creates an earthquake, destroying the kingdom.
The country only appears in the episode King Yakko.