Illustration: James E. Haff and Dick Martin / International Wizard of Oz Club (1980)
National Geographic Map of the Day has a really neat (and zoomable) fictional map of the Marvelous Land of Oz, illustrated by James E. Haff and Dick Martin for the International Wizard of Oz Club (apparently there is such a thing) based on L. Frank Baum's books The Wizard of Oz and The Marvelous Land of Oz.
And did you know that when the movie version of The Wizard of Oz opened in 1939, the very first theater that screened it was in the small town of Oconomowoc, Wisconsin? Three days later, the movie premiered at Grauman's Chinese Theater in Hollywood.
Link - Thanks Marilyn Terrell!
http://ngm.nationalgeographic.com/map/map-day/2008/08/12
Baum was prolific and wrote many other series for children. The public, and his publishers, pushed him for more tales from the "Land of Ahs", so he transported most of them into Oz and created all the places on the map.