The , also called the Seta River (瀬田川 Seta-gawa) and the Uji River (宇治川 Uji-gawa) at portions of its route, is the principal river in Osaka Prefecture on Honshū, Japan. The source of the river is Lake Biwa in Shiga Prefecture to the north.
The Yodo River, usually called the Seta River in Shiga Prefecture, begins at the southern outlet of the lake in Ōtsu. There is a dam here to regulate the lake level. Further downstream, the Seta flows into Kyoto Prefecture and changes its name to the Uji River, and then merges with two other rivers, namely the Katsura River and the Kizu River in Kyoto Prefecture. The Katsura has its headwaters in the mountains of Kyoto Prefecture, while the Kizu comes from Mie Prefecture. From the three-river confluence, the river is called the Yodo River, which flows south, through Osaka, and on into Osaka Bay. It is a source of water for irrigation and is used for power in the process of hydroelectricity.