The lake is located among high mountains in a remote corner of Oz. Unusually for a mountain lake in an inland location, Orizon is a saltwater rather than a freshwater body. It has been compared to an inland sea. It bears five islands that make up the Ozure Isles, an independent polity with the Sapphire City as its capital. (The Giant Horse of Oz)
Lake Orizon had long supported a population of Hippocampus so big that the residents of the Isles could ride them for transport. This breed of Hippocampus however, was eaten out of existence by the monster Quiberon (an extremely rare example of biological extinction in Oz) where exotic life forms flourish more dramatically, perhaps, than anywhere else. Fortunately after he turned Quiberon into a stature, the Wizard of Oz used his magic to reconstitute the extinct creatures from their bones, so that the breed lives once more.