| Makomanai River | |
| Name Other: | 真駒内川 |
| Name Etymology: | rear river |
| Subdivision Type1: | Country |
| Subdivision Name1: | Japan |
| Subdivision Type2: | State |
| Subdivision Name2: | Hokkaidō |
| Subdivision Type3: | Region |
| Subdivision Name3: | Ishikari |
| Subdivision Type4: | District |
| Subdivision Name4: | Sapporo |
| Subdivision Type5: | Municipality |
| Subdivision Name5: | Sapporo |
| Length: | 21km (13miles) |
| Source1: | Bankei Pond |
| Source1 Location: | Sapporo, Hokkaidō, Japan |
| Source1 Coordinates: | 42.8806°N 141.26°W |
| Source1 Elevation: | 913m (2,995feet) |
| Mouth: | Toyohira River |
| Mouth Location: | Sapporo, Hokkaidō, Japan |
| Mouth Coordinates: | 43.0039°N 141.3447°W |
| Basin Size: | 37km2 |
is a tributary of the Toyohira River in Sapporo, Hokkaidō, Japan. It has a length of 21km (13miles) and has a watershed of 37km2.
Flowing from in the mountains, the Makomanai River's upper course is called, too. Its middle course flows through a narrow valley about 200m (700feet) wide in the area. Running north, it merges with the Toyohira River at Makomanai area. The Toyohira River flows through the Sapporo city's center. Makomanai means rear river in the Ainu language.[1]
Edwin Dun, an Oyatoi gaikokujin, began development of Makomanai in the 1870s with a pioneer stock farm.[2] The valley of Tokiwa remained undeveloped for a long time. Flood control projects were begun in the later half of 20th century; straightening the river course in the 1960s.[3] Now a residential zone exists along the northern half of Tokiwa along National Route 453. Houses cover the surrounding hilltops around Makomanai. At the confluence with the Toyohira River is Makomanai Park. Cherry salmon migrate to and spawn in the park every year.