Ōtsu serves as the capital city of Shiga Prefecture in Japan, situated on the southern and western shores of Lake Biwa. It occupies the southwestern portion of the prefecture, stretching along the lake's southwest shore in an L-shaped configuration. The city ranges from densely populated alluvium depressions near the water to sparsely populated hilly and mountainous areas to the west and south, including the Hira Mountains and Mount Hiei.