DIY Guide to Fly Fishing Firehole River in Yellowstone National Park

The Firehole River is a famous and storied destination for serious fly fisherman and runs completely within the boundary of Yellowstone National Park.

The Firehole River is born at Madison Lake in the western portion of Yellowstone and flows for 33 miles before joining with the Gibbon River to create the Madison River.

The Firehole has been called the “strangest trout stream on Earth.” This spring-fed river flows past some of the favorite attractions of Yellowstone National Park and through the most active geyser basins in Yellowstone including Old Faithful.

This creates a unique fishing experience as anglers are often fishing against a backdrop of steam rising from a gurgling hot spring.

About Firehole River

The Salmon Fly hatch starts early on the Firehole River and works it way downriver toward the Madison River.

Brook trout, browns and rainbows average 10-14 inches in the Firehole. The river is born a cold mountain stream, like many others. Hot water from geothermal features first enters the river in the Upper Geyser Basin. In 30 miles, the Firehole River warms almost 30 degrees. This warm water temperature facilitates year-round insect activity and trout growth. The Firehole River mainly flows through flat prairie type terrain. At one point the Firehole disappears down a canyon which offers some great fishing at its lower end.

Best Places to Fish the Firehole River

The Firehole River is accessible by the Grand Loop Road, Old Faithful Road and several trailheads. The best fishing often requires a hike, but it is worth it. The map below shows some of the best spots to fish the Firehole River.

Firehole River Map and Fishing Access Sites

Best Time to Fish the Firehole River

The best time to fish the Firehole is in the spring (June), as it is one of the first rivers in the Park to clear, and then again in the fall (September/October).

Firehole River Hatches and Flies

June brings caddis and mayflies and small low-profile flies are a must. Pale Morning Duns (PMDs) and Baetis hatch in June with the PMDs staying until July. Effective dry-fly patterns include Hendricksons, Quill Gordons, Adams, Pale Morning Duns, Blue-Winged Olives, and midge patterns.

From July through mid to late August, the Firehole effectively shuts down. The water warms enough that the trout move into the cooler tributaries like the Little Firehole, Sentinel, Fairy and Nez Perce creeks.

Caddis and midges appear again in September, staying until the first frosts of late fall. Insects on the Firehole shrink dramatically as the season progresses, so should your flies.

Terrestrials hit their peak in late August and early September. Use a slim, sparse hopper or small ant or beetle for the best results.

The best flies for Firehole River are those that match the hatch the closest.

Firehole River Fly Fishing Tips

The Firehole provides excellent dry fly fishing and is an easily accessible, slow moving meadow stream that demands careful presentations and imitative flies for the prolific caddis and mayfly hatches it produces.

Fishing on the Firehole requires spring creek type tactics. Stalking and hiding your profile are often necessary to catch these wary trout. Small flies and long, thin tippets are needed.

While it is easy to wade the Firehole River, it is often better to fish from shore. The larger trout hang out near the undercut banks and weed lines. Fishing from shore gives you less risk of spooking the fish. The Firehole River fishes best on overcast, stormy days.

A 9-foot 5-wt fly rod with floating line is perfect for fishing dry flies and small nymphs on the Firehole River.  A tapered 9-foot leader, with tippet size 3X to 6X to match the flies you are throwing, is pretty standard.

Firehole River USGS Flow Charts

Firehole River Fishing Reports

There are a number of area fly shops and on-line retailers that publish Firehole River fishing reports. A few to check out are listed below:

• Montana Anglers
• Yellowstone Angler
• Fish the Fly Guide Service
• Grand Teton’s Fly Fishing
• Firehole Ranch

Firehole River Fishing Regulations and Precautions

The Firehole River is fly fishing only and rainbow and brown trout are catch and release only. Five brook trout may be harvested daily. If you plan to fish in late July or August you may find the Firehole closed to fishing due to high water temperatures.

Check with the park office before planning your trip and upon arrival. As the Firehole flows through geothermal areas it is best to stay on designated paths when hiking to avoid any hot surprises. The Firehole is in prime bear country, observe the usual precautions.

Looking for more places to fish in Yellowstone National Park? Check out our DIY Guide to the Best Fly Fishing in Yellowstone National Park.