| Rostoul River | |
| Pushpin Map: | Canada Ontario |
| Pushpin Map Caption: | Location of the mouth of the creek in Ontario |
| Subdivision Type1: | Country |
| Subdivision Name1: | Canada |
| Subdivision Type2: | Province |
| Subdivision Name2: | Ontario |
| Subdivision Type3: | Region |
| Subdivision Name3: | Northwestern Ontario |
| Subdivision Type4: | District |
| Subdivision Name4: | Kenora |
| Subdivision Type5: | Part |
| Subdivision Name5: | Unorganized Kenora District |
| Source1: | Embryo Lake |
| Source1 Elevation: | 381m (1,250feet)[1] |
| Mouth: | Hammerhead Lake |
| Mouth Coordinates: | [2] |
| Mouth Elevation: | 337m (1,106feet) |
| River System: | Hudson Bay drainage basin |
The Rostoul River is a river in the Unorganized Part of Kenora District in Northwestern Ontario, Canada.[3] [4] [5] It is in the Hudson Bay drainage basin, is a left tributary of the Gammon River, and is within Woodland Caribou Provincial Park.
The river begins at Embryo Lake and flows southwest to the north side of Telescope Lake, then leaves that lake at the west and heads west in the direction of Optic Lake, arriving at that lake's northeast end. It leaves the lake at the west and heads southwest to the southeast end of Glenn Lake, then leaves that lake at the northwest heading west to the southeast end of Hansen Lake, where it takes in the right tributary Domain Creek. The river leaves Hansen Lake at the northwest and heads northwest to the southeast end of Rostoul Lake, where it takes in the left tributary Haven Creek, then flows north and reaches its mouth on the south side of Hammerhead Lake on the Rostoul River. The Rostoul River flows via the Gammon River, the Bloodvein River, Lake Winnipeg, and the Nelson River to Hudson Bay.