Filmed primarily in Kingman, Kansas, using local extras. The children at the school where the Scarecrow and Tin Man first land in America had to be coached to speak in New Jersey dialect.
A story involving the Scarecrow and the Tin Man coming to America and visiting Dorothy in Kansas, was actually written by L. Frank Baum, the author of The Wizard of Oz and its sequel The Marvelous Land of Oz. He wrote a set of vignettes called Queer Visitors From the Land of Oz, printed in newspapers in 1904-1905. The duo were accompanied by characters from the second book: Jack Pumpkinhead, the Sawhorse, the Woggle Bug, and the Gump. At the same time, Baum's former business partner W.W. Denslow published a similar feature called The Scare-crow and the Tin-Man, which also featured the Cowardly Lion, with the most prominent story arc placing the trio in New York. Due to a copyright arrangement, Denslow's feature was not allowed to include the character Dorothy or the name of Oz. While the bulk of both authors' work is considered classic and timeless, these stories are noted for being uncomfortably dated, and are rarely reprinted. However, all their copyrights have expired into the public domain, so anyone may legally upload these stories onto a website.
In the movie's universe, L. Frank Baum's book The Wizard of Oz is very well known, but no one ever mentions the most famous medium of the story: the movie The Wizard of Oz (1939). Presumably this omission was done to avoid any accusation of plagiarism. While the 1900 book is in the public domain, the 1939 movie isn't.