Usayama-jo Castle was a yamajiro (a castle built atop a mountain to take advantage of the mountain's topography) constructed in the Medieval Period, and its ruins can be found near Nishikoori, Otsu City, Shiga Prefecture.
宇佐山城（うさやまじょう）は滋賀県大津市錦織に残る、中世の山城である。