Tsahya, an island nation, is one of the remaining areas in Final Fantasy XI yet to be revealed. What is known so far (which is very little) is that it is located somewhere to the south of the continents of Quon and Mindartia. It was for some time speculated to be the homeland of the cat-like race Mithra, however the Wings of the Goddess expansion pack confirmed their homeland to be the continent of Olzhirya, also located to the south. It is also the home of Yasmeel.
Items available which relate to Tsahya are the Tsahyan Mask and possibly the Southern Mummy.