Desert Province
The fifth province in Twilight Princess, it is accessable only by first going to Telma's Bar in Castle Town. After you have received her letter, check the map for Auru's location, and talk with him, answering yes to his question, and you will recieve Auru's Memo. Give it to Fyer at the cannon in Lake Hylia so you can take the "Oasis Flight" to the Desert Province. There is only one location in this province, the Gerudo Desert.