Firehole River, Wyoming
Yellowstone National Park — Fly fishing through geysers on one of the world's most unique trout streams
The Firehole River in Yellowstone National Park is unlike any other trout stream on earth. Flowing through the world's most concentrated geothermal landscape — past Old Faithful, Midway Geyser Basin, and the Lower Geyser Basin — the Firehole is a thermal spring creek warmed to unusual temperatures by the volcanic activity that defines the Yellowstone plateau. The result is a river with inverted seasonality: the Firehole fishes best in spring and fall when its thermal warmth is an asset, and becomes uncomfortably warm in summer when geothermal input pushes temperatures above ideal trout ranges.
The river runs through open meadows between geyser basins, creating a surreal fishing environment where bison graze on the banks, geysers erupt in the background, and wild brown and rainbow trout rise in the steam-veiled water. This is arguably the most photogenic trout stream in North America — and the fish are genuinely wild and large, averaging 14–18 inches throughout the most productive sections.
The Firehole is a spring creek in character despite the unusual thermal influence — moderate gradient, weedy margins, clear water, and selective trout that require careful presentations. The early season (mid-June, when the park opens the Firehole to fishing) offers exceptional Caddis and early BWO activity before summer temperatures restrict the most productive hours to early morning and evening.
September and October are the finest months to fish the Firehole — temperatures moderate, hatches return, brown trout begin moving toward spawning aggression, and the fall crowds of the main park roads thin considerably.
Midway Geyser Basin — Firehole Lake Drive
Access from the Firehole Lake Drive loop off US-191. Multiple pull-offs with direct river access. Morning fishing here before crowds arrive is exceptional.
Fountain Flats — Lower Meadow
Extensive meadow section accessible from the Fountain Flats area. Bison frequent this section — maintain safe distance. Classic spring creek dry fly water.
Firehole Canyon — Below Madison Junction
Below the main meadow section, the river enters a short canyon. Different character — faster water, less technical, more attractor-friendly.
Brown Trout
Dominant in the lower and middle sections. Wild Yellowstone strain averaging 14–18 inches. Most active in fall during pre-spawn. Respond well to streamer and nymph presentations.
Rainbow Trout
More common in faster canyon sections. Yellowstone strain rainbows — highly colored, strong fighters. PMD and Caddis hatch timing brings them to the surface.
Brook Trout
Present in some tributary streams feeding the Firehole. Non-native but established. Smaller than the main river trout but willing dry fly fish.
The Firehole becomes too warm for productive fishing in July and August between 10am and 6pm. Fish the first 3 hours of daylight and the last 2 hours of light.
September after Labor Day is the ideal Firehole visit — tourists thin dramatically, temperatures moderate, and fall BWO hatches begin.
Bison own the Firehole meadows — give them wide berth. Encounters are common and they have the right of way.
The NPS Yellowstone fishing permit is separate from a Wyoming fishing license and available at park visitor centers. Get both before you fish.
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