This Eastern Idaho river starts as a large spring bubbling out of a mountain outside of Ashton, Idaho. The spring water maintains the river at a consistent temperature that just so happens to be perfect for trout.


I have fished Warm River in every season, and thanks to the consistent water temperature it always seems to be productive. Like most rivers out West, expect runoff sometime during late spring and early summer. However, other than that this river is a dream.
Winter Fishing
While I lived in Eastern Idaho this was one of my favorite winter destinations. If we could endure the air temperature we knew we could catch fish.
The coldest we tried fishing it was 18 degrees Fahrenheit. We learned it wasn’t worth it because the eyes of our guides kept freezing up with ice. If you plan on fishing it in the winter wait until daytime temperatures are in the thirties. You will have more fun and be more comfortable.
Also, if you fish this river in the winter fish close to the car. A slip into the water at low temperatures is dangerous. You need to be able to get out of the elements quickly.
Side Trips
Mesa Falls: If you are fishing Warm River during the summer or early fall check out upper and lower Mesa Falls. They are beautiful and a great place to take those who don’t fish (I know it is hard to believe there are people out there who don’t.) Note: these falls are not accessible most of the year due to snowpack.
Bread Fish- When you arrive at Warm River you will see a pullout with what looks like a gum/candy machines. It is filled with fish food. Take a few quarters and get some to feed the fish. These rainbows are ridiculously huge, but this stretch of the river is closed to fishing.
Warm River Overview:
Fishing Quality: Excellent. There are large rainbows, browns, and whitefish. You might find a brook trout too.
Skill Level: Fairly good spot for beginners. A great place to learn how to fish nymphs under an indicator.
Equipment: 5 or 6 weight. Floating Line
Family Friendly: Yes. As mentioned above there are a couple of fun side trips if the fishing is slow.
Fly Patterns:
- Rubber leg stonefly nymphs– Black and Olive
- Midges– Black and Olive
- Salmon Fly Dries– (If visiting during spring or summer.) If salmon flies are hatching on the banks, and you don’t have a salmon fly pattern you will regret it. You can substitute a large stimulator if you don’t have a salmon fly on hand.
- Other than that stick with the general patterns I recommend for a trip out to Idaho.
Notes: Robinson Creek and the Henrys Fork flow nearby. Hence why this area is called Three Rivers. If the bite is off at Warm try one of the others.
Warm River Brown Salmon Fly
Hope that helps.