Fly Fishing Clarks Fork Yellowstone River - Upper

Fly fishing Upper Clarks Fork Yellowstone River in Wyoming offers a raw, untamed experience unlike many rivers in the Northern Rockies. Flowing from high in the Absaroka and Beartooth ranges, this section cuts through some of the most dramatic canyon country in Wyoming before exiting into Montana. With towering cliffs, rugged access, and wild trout populations, the Wyoming Clarks Fork is a river for anglers who crave adventure and solitude.

The Wyoming portion of the Clarks Fork is a freestone river in its purest form. The gradient is steep, producing long canyon rapids, turbulent pocket water, and plunge pools carved from volcanic rock. In between these powerful flows lie deep green runs and eddies that harbor strong trout. It’s a river that demands wading skill and careful reading of water, rewarding persistence with wild fish that thrive in its cold, oxygen-rich currents.

Trout species in the Wyoming Clarks Fork include Yellowstone cutthroat, rainbow, and brown trout. Cutthroats dominate the higher reaches, while rainbows and browns become more common as the river approaches the Montana border. Fish sizes are healthy, with plenty of trout in the 12–16 inch class and opportunities for larger browns that push well past 20 inches, especially in fall when they migrate through canyon waters.

Seasonal hatches are diverse but can be challenging to match given the river’s variable flows. Spring brings blue-winged olives and midges, while early summer is marked by salmonflies and golden stones that get big trout moving on the surface. As the season progresses, caddis and PMDs take over, with terrestrial fishing along rocky banks providing excellent mid- to late-summer action. Fall brings back strong BWO hatches, and streamer fishing becomes the ticket for trophy browns.

Flows between 150 and 500 CFS make for the safest wading conditions, though some parts of the canyon are never easy to traverse. Above this range, the river becomes powerful and dangerous, limiting effective access to shoreline fishing or float trips where permitted. Access points are limited compared to Montana — anglers rely on pull-offs along Highway 120 and select U.S. Forest Service trailheads. Because much of this section flows through steep canyon walls, many stretches require hikes into rugged terrain.

For anglers willing to put in the effort, fly fishing the Wyoming Clarks Fork Yellowstone River is unforgettable. With native cutthroats, wild rainbows, trophy browns, and scenery that rivals any Western canyon, this river rewards preparation and persistence. It’s a must-fish for adventurous anglers looking for solitude, powerful water, and the chance at some of Wyoming’s most impressive freestone trout.