The Jalacasco Islands are a group of islands in the Nonestic Ocean. In Pirates in Oz, Samuel Salt said that he got stuck for seven years near the islands because there was no wind to move his ship. On the map of the countries surrounding Oz by James E. Haff and Dick Martin, they are shown to be south of Boboland.
The name Jalacasco may be based on Jalisco, a Mexican state.