Western Thanalan is an area of Thanalan and connects to Central Thanalan and the city of Ul'dah. You can also catch a ferry to the city of Limsa Lominsa from the western edge at the ferry docks.
The main hub of the area is at Horizon, which is centrally located. The dungeon Copperbell Mines is not far from here. The area to the far north-west is gated off so we were unable to uncover this portion of the map.