Cross-posted from here.
Ozamaland shows up in Captain Salt in Oz, but it also had a brief mention in the earlier Pirates in Oz as well. The latter book has Captain Salt mentioning that he had wanted to explore Ozamaland, but ended up having to deal with a mutinous crew instead. In Captain Salt, he finally reaches it, but not until near the end of the story. It's located on the long continent of Tarara (adjacent to the continent of Boomdeeay, perhaps?), far across the Nonestic Ocean from the island-continent on which Oz is located. Tarara is divided into two countries, Ozamaland on the east and Amaland on the west. Ozamaland is mostly desert and jungle, and its people tend to live in primitive tents and huts, and wear white robes and turbans. Animals there include white camels and elephants, as well as feathered flying snakes and scaled creeping birds with fangs. Unfortunately for us, John R. Neill didn't draw either of these mixed-up creatures. Amaland is a plains country, where the people dress in gray and ride around on gray horses, which suggests to me that Ruth Plumly Thompson was aiming for a Mongolian feel to the place. The capital of Ozamaland is the White City of Om, named after its first king. Traditionally, this was the home of one thousand noble families, as well as that of the king and his nine judges, the square-hatted Ozamandarins. These judges held most of the power in the kingdom, with the king mostly being a figurehead, although the royal family seems to have been unaware of this power grab. I would imagine it was gradual, but when the only remaining heir was a boy named Tazander Tazah, the Ozamandarins decided to get rid of him entirely and divide the country among themselves. They enlisted the help of Boglodore, the Old Man of the Jungle, but he remained suspicious of them and used magical protections to keep Tandy alive as sort of a bargaining chip.
When Tandy returns home in the company of Captain Salt, the Ozamandarins try to keep control by locking him in a tower, but he and his friends conquer the judges with the help of tumbleweeds and creeping vines from the island of Patrippany. Boglodore then throws them into the sea with help from his Umbrellaphant, Umbo. Tandy also makes an ally of Chunum the Sheik, leader and representative of the thousand desert tribes. And while Tandy is officially restored to his throne, two other major political changes come about as well. For one, while not officially abdicating, Tandy decides to remain on the crew of the Crescent Moon, leaving Chunum to serve as his regent. Also, the boy king declares his country to be an official protectorate of Oz, which the people cheer, but they might still be swept up in the excitement of having their king restored and the desert dwellers receiving more of a voice in government. I wouldn't think most people, no matter how poorly they fared under previous rule, would be that happy about their homeland becoming a colony. I like to think Ozma's rule over Ozamaland was pretty much entirely symbolic, but it's never discussed. Chunum also aims to make peace with the neighbors in Amaland, stating that the Ozamandarins encouraged a state of enmity between the two nations to protect their own power. No one actually visits Amaland during the course of the story, however, so that could be a potential premise for a new story. I wonder if it has its own Grey City to parallel the white one in Ozamaland. One of the Oz holiday cards sent out by the late Fred Meyer proposed another idea involving the nations of Tarara, specifically Tandy falling in love with the Princess of Amaland, and the possible unification of the two lands. Honestly, though, I don't know that I'm too anxious to work with Tarara myself, because despite interesting details like the fauna, I don't think Thompson does all that much to make a truly distinct place. Then again, that's something that a new story about the continent could change. I've heard tell of an upcoming book called The Umbrellaphant in Oz, by Carlos P. Silva and Marin Elizabeth Xiques, but I don't know enough about it to say whether Tarara features in it. I wouldn't be surprised if it does, though. Thompson did write a poem about the Umbrellaphant in which she suggested he'd become Tandy's royal steed, but I'm not sure whether this should be counted as canonical.