Emerald City
From Jenny Everywhere Wiki
The Emerald City was the capital city of the Land of Oz. Just as the city is in the center of Oz where the four quarters of the Munchkins, Gillikins, Winkies, and Quadlings come together, so too is the Emerald Palace of Queen Ozma in the center of the city.
Many famous and accomplished Ozians live in the city.