| Ruby River | |
|---|---|
 Fly fisherman on the Ruby River | |
  Location of mouth | |
| Location | |
| Country | United States |
| State | Montana |
| Physical characteristics | |
| Mouth | |
• coordinates | 45°31′13″N 112°20′25″W / 45.52028°N 112.34028°W[1] |
• elevation | 4,642 feet (1,415 m)[1] |
| Length | 76 miles (122 km) |
| Basin size | Snowcrest Range and Gravelly Range |
| Discharge | |
| • location | near Twin Bridges |
| • average | 199 cu ft/s (5.6 m3/s)[2] |
| Basin features | |
| River system | Missouri River |
The Ruby River is a tributary of the Beaverhead River, approximately 76 mi (122 km) long, in southwestern Montana in the United States. It rises in the Beaverhead National Forest in southwestern Madison County between the Snowcrest Range and the Gravelly Range. It flows north through the Ruby River Reservoir, past Alder, then northwest, flowing between the Tobacco Root Mountains to the northeast and the Ruby Range to the southwest. It joins the Beaverhead near Twin Bridges. The Beaverhead becomes the Jefferson River 2 mi (3.2 km) downstream where it joins the Big Hole River.
The river has also been known by these various names: Pah-mamar-roi, Pak-sam-ma-oi, Pashmaroi, Passamari, Philanthropy River, Stinking Water Creek, Stinking Water River, Stinkingwater River.[1]
The Ruby is a Class II river for stream access for recreational purposes.[3]