The name "Oz" refers specifically to the great kingdom at the world's heart, which is surrounded by the vast Deadly Desert, beyond which lie other realms such as the Forest of Burzee and the kingdoms of Ix and Ev. The Land of Oz has miraculous properties, conferring complete immortality and immunity to aging upon all living beings within its borders and granting sentience and the ability of speech to all animals that enter it. Oz is divided into four nations - the Munchkin, Quadling, Winkie, and Gillikin Countries - which are all ruled from the Emerald City in the land's very center.
Around the turn of the 20th Century, the four lands of Oz were ruled by four witches, two good and two evil, while the Emerald City was ruled by Oscar Z. Diggs, the "Wizard of Oz", a traveling showman from Earth who had fooled the people of Oz into thinking he was a real magician. Another visitor from Earth, Dorothy Gale, destroyed the two wicked witches and returned to Earth with Diggs. Not long after, Princess Ozma, the long-lost descendant of the old kings of Oz, was restored to the throne. Dorothy and the Wizard both eventually returned to Oz and took up permanent residence there, and Diggs even learned real magic under the good witch Glinda and became Ozma's loyal court magician.
- The Wizard of Oz is known as a work of fiction in New Earth, Earth-C and Earth-One.
- The other-dimensional realm of Doov resembles Oz in a few superficial ways, and after visiting Doov Supergirl theorized that tales of Doov may have inspired L. Frank Baum to write the Oz books.
- The Land of Oz was created by L. Frank Baum in his novel The Wonderful Wizard of Oz, which was adapted into The Wizard of Oz by MGM Studios in 1936. The DC Universe version of Oz follows very closely to Baum's books; when Fastback remarks that Oz looks nothing like the movie, the Cheshire Cat tells him, "The book is always different from the movie."