Philadelphia
Philadelphia is Button-Bright's home, far from the country where he is now lost.
First named in The Scarecrow of Oz, ch. 8
"His home used to be in Philadelphia, I think; but I'm quite sure Button-Bright doesn't belong anywhere."
Where this is
placed In our world worked out
read out of the chapters cited on this page, not stated in any one sentence of them
What the books say it is
region America 1 chapter
The other boy was an American from Philadelphia and had lately found his way to Oz in the company of Trot and Cap’n Bill.
The Lost Princess of Oz, ch. 5