| Rainy River | |
| Pushpin Map: | British Columbia |
| Pushpin Map Caption: | Mouth of Rainy River |
| Subdivision Type1: | Country |
| Subdivision Name1: | Canada |
| Subdivision Type3: | Province |
| Subdivision Name3: | British Columbia |
| Source1: | An unnamed lake north of Tetrahedron Peak |
| Source1 Location: | Pacific Ranges |
| Source1 Coordinates: | 49.6289°N -123.545°W |
| Source1 Elevation: | 1068m (3,504feet)[1] |
| Mouth: | Thornbrough Channel |
| Mouth Location: | Port Mellon |
| Mouth Coordinates: | 49.5211°N -123.48°W |
| Mouth Elevation: | 0m (00feet)[2] |
The Rainy River is a short river that enters the Thornbrough Channel at Port Mellon, British Columbia, Canada. While it does come close to doing so, it never enters Tetrahedron Provincial Park.
The Rainy River originates in a small unnamed lake just north of Tetrahedron Peak. The river, shortly after exiting the lake, likely drops over a fairly tall waterfall as it drops down a headwall. The river flows southeast for about 3.6 km before turning south and flowing that way for about 9.8 km to its mouth at Port Mellon. The river does not receive any major tributaries.