The is a continuation of two other rivers, the Hozu River, a small, speedy river which begins in the mountains near Kameoka and then slithers through the mountains separating Kameoka and Kyoto; and the Ōi River (大堰川 Ōi-gawa), which emerges from those mountains and expands into a shallow, slow-flowing river until Togetsukyo Bridge in Arashiyama. From that point forward, the river is referred to as the Katsura River, and its flow continues for several kilometers through Osaka Prefecture until it joins the Kamo and Uji rivers.