Yellowstone Park

Big action here are brown trout runs in the Lewis, Madison, Gibbon and lower Firehole (below the falls) rivers. Other than that, the BWOs are active on the Firehole, Madison, and Gibbon rivers. Be prepared for winter conditions throughout the Park. That means have proper clothing and driving habits.
Fly Patterns to use:
Brook’s Sprout-Baetis
Egan’s Silver Bullet-Baetis
Antonio’s Adult BWO