Lanayru Province
The Lanayru Province is part of the province system of Twilight Princess. It is located west (east for Wii) of Eldin Province, east (west) of Peak Province, and occupies the majority of the map. It includes Hyrule Castle, Hyrule Castle Town, Lake Hylia, Zora's Domain, and Zora's River, as well as the third dungeon, Lakebed Temple. It is protected by the Spirit of Light Lanayru. The Lanayru Province is named for the Goddess of Wisdom, Nayru.
Lake Hylia
Lake Hylia is situated at the bottom of Zora's River. At the bottom of the lake, the Lakebed Temple can be found. The lake is also home to two business partners called Fyer and Falbi. They own, between them, a giant cannon that can fire Link from Lake Hylia to higher ground around it, and also to the Gerudo Desert.
Upper Zora's River
Connecting Lake Hylia and Zora's Domain is Zora's River, but only the upper riverbank is traversable on foot. Here, Link can find Iza, who will allow Link to canoe down the river and play a mini-game simultaneously. A short-cut to northern Hyrule Field exists here as well.
Fishing Hole
Existing as a sub-area to Upper Zora's River, Link can fish with various lures here. Owned by Hena, the Fishing Hole is the only place in Twilight Princess that experiences season change, which is triggered by leaving and entering the area. Hena will allow Link to either fish alone or with herself, but at an extra cost. Link can also play Hena's mini-game, called Rollgoal, in order to use the frog lure.
Zora's Domain
The headwaters of Zora's River, Zora's Domain is the home of the Zora race. Initially frozen, the waters of the river must be thawed in order to refill Lake Hylia. It is the main source of water in all of Hyrule. In the water at the head of the domain there is a location Prince Ralis refers to as Mother and Child Rocks.
Zora's Throne Room
The Zora's Throne Room is located at the top of Zora's Waterfall and far above Zora's Domain. It is home to the Zora Royal Family and seems to be main source of all the water in Hyrule. It is much larger than the Throne Room featured in Ocarina of Time and features a deep pool-like area that can be explored using the Zora Armor and Iron Boots. Zora's Throne Room also contains a Warp Point which Wolf Link can access after defeating three Shadow Beasts inside the frozen Throne Room. This warp point is needed to unfreeze both the Zora's Throne Room and Zora's Domain.
Castle Town
Castle Town is located just below Hyrule Castle, and is accessible from the east, south and west. Many businesses reside there, including Telma's Bar, where Link may gather information from the group of vigilantes working to restore peace in Hyrule. Shops there are expensive, but if Link donates enough money to Malo, found in Kakariko Village at Malo Mart, then the new Malo Mart opens up in Castle Town.