Sidgler Province is located west of Yungechandler Province. This is the main fief of Duke Madras. Sidgler Province can only be accessed through the pass guarded by Xith Castle in Yungechandler Province. The capital of the duchy is in this province.
From the map, the land of Sidgler could be a valley surrounded by Lizgna Mountains and Civilink Highlands. The valley was large enough to be a province in and of itself. Some parts even neared the coast. There was only one entrance, it was the pathway near which Xith Castle was built. The fact that only one castle was required to defend Sidgler was probably why Duke Madras made it his headquarters.