Rumoi River

Rumoi River 留萌川
Aerial view of the city of Rumoi, with the Rumoi River at right
Native name	Rumoi-gawa (Japanese)
Location
Country	Japan
State	Hokkaidō
Region	Rumoi
District	Rumoi
Physical characteristics
Source	Mount Poroshiri
• location	Rumoi, Hokkaidō, Japan
• coordinates	43°57′46″N 141°50′10″E
• elevation	730.2 m (2,396 ft)
Mouth	Sea of Japan
• location	Rumoi, Hokkaidō, Japan
• coordinates	43°57′22″N 141°38′33″E
• elevation	0 m (0 ft)
Length	44 km (27 mi)
Basin size	270 km2 (100 sq mi)
Discharge
• average	13.3 m3/s (470 cu ft/s)

Rumoi River (留萌川, Rumoi-gawa) is a river in Hokkaidō, Japan. The Rumoi is 44 kilometres (27 mi) in length. It traces its source to Mount Poroshiri 731 metres (2,398 ft) in the Hidaka Mountain range, and flows across Rumoi Subprefecture in the west of Hokkaidō and empties into the Sea of Japan. The mouth of the Rumoi River is in the city of Rumoi.