Mountains of the Moon
The Mountains of the Moon are home to a friend of Atmos who made him his first pair of iron boots.
First named in The Hungry Tiger of Oz, ch. 15
"Well," said Atmos, "a friend of mine who lives on the Mountains of the Moon, made me a pair of iron boots.
Where this is
placed Beyond the desert worked out
read out of the chapters cited on this page, not stated in any one sentence of them
Hungry Tiger of Oz ch15: Atmos's friend lives there and he 'dove from the tip of the Moon' to reach the earth — a sky/celestial realm like Sky Island, not Earth or Oz.