by James Marsh
Copyright 2020 James Marsh
Great Destination Streams
The Firehole River Is one of the most unique trout streams in the nation. It is a very strange
stream located in Yellowstone National Park. It flows past many of the parks prime attractions for
thirty-three miles. It starts in the southwest corner of Yellowstone National Park at Madison Lake
and flows into the Madison River. Fish the river on an early summer morning and you will probably
think that you are dreaming or that you have died and gone to hell while you were on a fly-fishing
trip with all the steam rising from the geysers. It is part freestone stream and part spring creek.
The main difference is the springs are adding hot water from geysers.
When the season first opens in Yellowstone Park, the warm water helps by bringing the water
temperatures up. The Firehole may be the only stream in the park that you can fish during the
spring runoff time for many other streams. Later on in the season, right the opposite situation
takes place. The added warm water from the geyser basins will raise the water temperatures
beyond that optimal for trout. It is usually September before water temperatures get back in the
preferred range for trout.
The water temperatures in the Firehole River can vary from one place to another depending on
the relationship of the section of the stream to the gysers. Being at the right place on the river at
the right time is the key to fishing the stream. The geyser locations add hot water and the
tributaries add cool water. A themometer is very useful in helping to determine where to fish. The
Firehole River is the first stream in the park to become fishable. It may be the only one you can
fish on opening day of the season.
Above Kepler Cascades, the small river flows through some meadows and a canyon. The river is
closed from the Firehole Bridge a mile and a half above Old Faithful to the bridge at Biscuit Basin,
about a mile and a half downstream of Old Faithful. This protects the fragile Upper Geyser Basin.
One of the most underfished sections of the river is the uppermost portion. It can be accessed
from the Bechler River Trail. Above the Kepler Cascades, the fish are all brook trout. You can
access the river below Kepler Cascades from the Firehole Bridge on the Grand Loop Road
upstream of Old Faithfull. You can only fish upstream from the bridge to Kepler Cascades.
Below the Biscuit Basin Bridge, the beautiful river flows through some large meadows. The
stream varies in width and depth flowing through a series of curves. Riffle sections connect the
meadow sections of the stream where the water generally has a smooth surface and slower flows.
This is always a favorite section of the river to fish in the early season.
The upper half of the eight mile long section of the river from Sentinel Creek to Biscuit Basin is
also easily accessed from the nearby Grand Loop Road. The lower half of this section which is
about four miles long, requires a short hike from the road. Naturally, is is also less crowded than
Below Sentinel Creek the Firehole River flows through area of alternating meadows with lots of
weeds and riffle sections for the first couple of miles downstream. A little further downsteam there
are more riffles than meadows because the gradient of the stream decreases all the way to the
Firehole Falls. The last couple of miles of the river, below the falls, consist of fast riffles and runs. It
flows through a canyon all the way to its confluence with the Gibbons River to form the Madison
The Firehole's trout are usually not as large as those found in many of the other streams in the
park. The trout are rainbow and brown trout that average from seven to twelve 12 inches long.
Some may go up to sixteen inches or better. The last two miles of the river, below Firehole Falls,
gets some spawning browns from the fall migration of Hebgen Lake trout. Some of these fish may
go up to twenty-four inches long. From Sentinel Creek north to the Madison River, a distance of
about six miles, the Firehole River is accessible from the Grand Loop Road in its upper four mile
long section. Below the falls, the river is accessible from Firehole Canyon Drive but only in a few
Little Firehole River and the Upper Geyser Basin adds a lot of water to the main river. The Little
Firehole starts in a meadow about four miles upstream from its confluence with the Firehole. It
drops off from the flat meadow section where it begins and flows through a deep canyon for about
two miles. Mystic Falls is a mile upstream of the Little Firehole Rivers confluence with the main
stream. Below the falls, the lower mile long section is a meadow stream with lots of deadfall
timber, pockets, undercut banks and pools. The trout in the lower section below the falls are
typical size Firehole River brown and rainbow trout. Keep in mind that fish will move into this
stream in the cooler water during the warm summer. Above the falls, cutthroat trout and brook
trout between four and ten inches long are present. The river is accessible from the Biscuit Basin
parking area on the Grand Loop Road.
Iron Spring Creek is a tributary of the Little Firehole River. It enters the stream a few hundred
yards upstream of the confluence of the Little Firehole and the Firehole River. Like the Little
Firehole River, this stream also starts on a plateau and cascades down to the Biscuit Basin area.
The lower two miles of the stream is fishable. It flows through the lower meadows curving around
through deadfalls of timber, pools, riffles and small runs. It is also accessible from the Biscuit
Basin parking area. The fish are the same fish as the Firehole River trout in this area. Larger fish
will move out of the main Firehole River into this stream during the hot summer months and can
run up to sixteen inches long.
Sentinel Creek is another tributary steam of the Firehole River. It's a small stream of low gradient
with some deeper holes and undercut banks. During the summer months when the main river is
very warm, some trout will move into the stream. These fish are usually nine to twelve inches with
some larger trout. The resident fish of Sentinel Creek, rainbow, brown and brook trout
average only six to ten inches long. Fish are present up to the falls with more brook trout in the
upper portion than browns or rainbows. Sentinel Creek is accessible from Fountain Flat Drive off
the Grand Loop Road about six miles south of Madison Junction.
The Firehole River is one of the my favorite streams to fish in the park. It is the most unusual and
interesting trout streams in the world. It would be a shame for any angler to visit Yellowstone Park
and not fish the river.
Firehole River Rainbow Trout
James Marsh fishing the Firehole River
Angie Marsh fishing the Firehole River