[1] Flowing down through the mountain valleys from its origins in Shibetsu, it is fed by tributaries (of which it has some 160[2]) including the Nayoro River (名寄川), then crosses the mountain plains, passing next through the more-constricted topography of Otoineppu before entering the Teshio Plain, where it meanders until flowing into the Sea of Japan at Teshio.

[3] At the Kawaguchi Site (川口遺跡) in Teshio, where the river enters the Sea of Japan, remains of some two hundred and thirty pit dwellings have been discovered, with deposits of the Zoku-Jōmon period as well as of the Satsumon and Okhotsk cultures.

[3] The first survey of the river was conducted by three men under Takahashi Sōshirō (高橋壮四郎), retainer of the Matsumae Domain, in Kansei 9 (1797), from its lower stretches as far as Otoineppu.

[3] After flooding continued to adversely affect the local farmers' potatoes, the Shōwa era saw further channel switching and the excavation of new waterways.

[1] Downstream, on the Teshio Plain, there is dairy farming, while near the river mouth there is salmon and trout fishing and also the prefecture's most intensive harvesting of shijimi clams.

[1] Nearer the river mouth is Rishiri-Rebun-Sarobetsu National Park, with more than a hundred species of flora including hamanasu, the Siberian lily, Japanese irises, and Hemerocallis esculenta (エゾカンゾウ).