Flathead River Brown Trout
Copyright 2019 James Marsh
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Fly Fishing The Flathead River Montana
Before we get started, please note that understanding
how the Flathead River is made up can be a little
confusing for those that are not familiar with it. This is
about the main stem of the Flathead River. There are
three other Flathead Rivers that are completely
separate rivers. They are the
North, Middle and South
Forks of the Flathead River and each of these three
rivers are covered in a separate section of our Perfect
Fly Stream section.

The Main Stem of the Flathead River is formed by the
confluence of the North Fork of the Flathead River and
the Middle Fork of the Flathead River. The South Fork
of the Flathead River enters the Main Stem of the
Flathead about five miles below Hungry Horse Dam that
forms the big Hungry Horse Reservoir on the South
Fork. This river's drainage is huge, including a large
part of Glacier National Park and the Bob Marshall
Wilderness Complex.

The Flathead River flows for about 158 miles. The huge
Flathead Lake divides the river into two sections, the
upper and lower section below the lake. From Flathead
Lake, the largest lake in the West, the Flathead flows
into the Clarke Fork River. Fly fishing the Flathead River
can vary greatly depending on the exact location you
fish. It's a big river.

The upper section of the river is a big, cold fast flowing
river. It is deep, and difficult to wade in most places and
during most of the season. Its water is cold even during
the Summer because it comes mostly from melting snow.
There are several braided sections of the river where it
divides into channels. It can be fished best from a drift
boat but attention to the stream flow is warranted. The
upper section has a population of rainbows and
cutthroats. Access to this section is good.

The lower section of the Flathead River is a tailwater.
Kerr dam regulates its flow which can change very
quickly. Like all tailwaters, special attention is needed.
Trout consist of browns and rainbows. It is considered a
prime pike stream but there are some larger size
rainbows and brown trout. The best fishing is just below
the dam. The river flows through a canyon called Buffalo

Flathead River Hatches and Trout Flies:
Contrary to what you might read, the fly your use is
important. It is true the trout will take the generic fly
patterns and attractor flies (we do sell those at Perfect
Fly) but if you imitate the most plentiful and available
insects (subsurface or top water) at the time you are
fishing, you will substantially increase your odds of
success. We have studied the aquatic insects in the
Flathead and have taken samples of the larvae to
develop reliable hatch charts.

There are variations in the tailwater sections and
freestone sections. There are variation in terms of the
time of hatches from the headwaters to the lower
sections. Midges are king in the tailwaters but other
species of insect exist.

Of all the mayflies, Blue-winged Olives and Pale Morning
Duns are the most common and important ones. There
are others including March Browns, Yellow Quills, Dark
Red Quills, Tricos, Green Drakes, Small western Green
Drake and others of far less importance.

In the caddisfly lineup you will find several different
species called Spotted Sedges as well as Green
Sedges. There are also Short-horned Sedges, Little
Sister caddis and October Caddis that can be very
important. Most of the other species are not so
abundant. The population is very diverse.

Stoneflies are very plentiful and they include the huge
Salmonflies, Golden Stoneflies and Little Yellow
Stoneflies. All three of these are plentiful and very
important especially during a hatch. .

During the summer you will find imitations of Carpenter  
ants, Japanese beetles and various size and colors of
hoppers work well.

Seasons follow the general Montana fishing season.
Late springtime has decent fishing opportunities and
hatches as good as they get on the Flathead River.
The Summer would be best time for fly fishing the
Early Fall presents good opportunities for big browns..

Fly Fishing Gear Tackle and Trout Flies
Type of Stream
Freestone Stream and Tailwater

Rainbow Trout
Brown Trout
Bull Trout (must be released)
Mountain Whitefish

Northwestern Montana

Large, about 158 miles long

Nearest Towns

3rd Sat of May through Nov 30th.
Plus a Catch and Release season

Very Good

Non-Resident License
State of Montana

National Weather Service Link

Fly Fishing Gear, Tackle & Trout

USGS Stream Flow Data:
Near Perma
Near Polson
Near Columbia Falls
100% Satisfaction Guaranteed
Photo Courtesy Steven Lamb
Options For Selecting Flies:
1. Email us (sales@perfectflystore.com)
with the dates you will be fishing this
stream and we will send you a list of our
fly suggestions. Please allow up to 24
hours for a response.

2. Call us 800-594-4726 and we will help
you decide which flies you need.

3. Email us (sales@perfectflystore.com)
with a budget for flies and we will select
them to match the budget and get them to
you in time for your fly fishing trip.

All orders are shipped free in the
U. S. Orders over $100 are shipped via
Priority Mail.  
Flathead River (Main Stem) Fishing Report:

02/10/16  The seasons is currently closed on the Flathead River but it isn't too early to start
planning your next fly trip. We have taken samples of the aquatic insects several times from
the Flathead River using professional equipment and gear and know what aquatic insects and
other foods are present. We don't go by trial and error in selecting flies and we don't guess at
it. Let us help you plan your next trip there: Send us an email at:
Flathead River Fishing Report:
October 10, 2019
(see bottom of page)
06/16/16 The runoff still has the river very high and dingy and this is likely to continue for the
next couple of weeks. We hope it ends earlier than normal this season. It started early.
07/12/16 Two good reports from the past week from customers fishing the river. The stream
levels are fine and wading possible in the normal places. There are a huge number of insects
hatching. Golden and Little Yellow stones, Green drakes, Yellow Quills, Spotted sedges,
Green sedges and more. Send us an email for a list of flies.
07/19/16 The Flathead is in very good shape in all sections. We are getting some good
reports from customers. There are a large number of hatches taking place.
07/26/16 Stream levels are still okay. The water is getting warmer and the Golden stoneflies
about done. Little Yellow stoneflies are hatching good. PMDs, Yellow Quills, Green drakes,
Spotted and green sedges (caddis) and other insects are hating good.
08/02/16 Spotted sedges, Green Sedges, Pale Morning duns, Yellow Quills and Little Yellow
stoneflies are hatching. Customers are sending in some good reports.
08/09/16 Two good reports from the past week. Sculpin streamers are working good early
mornings. Late afternoon egg laying caddis are bringing a lot of trout to the surface to feed.
08/16/16 There are lots of insects hatching and lots of trout being caught. The weather is
going to be much cooler near the middle of the week. Send us an email for a list of insects
hatching and flies to match them with.
08/23/16 Most anglers are using terrestrial imitations, hoppers, etc, but there are still a lot of
hatching insects. During the hatch, egg laying or spinner falls, imitations of these will
outperform the terrestrials.
09/06/16 The stream levels are in good shape and the weather and water temperature
cooler. Conditions are very good and our customers are catching plenty of trout.
10/13 There were some problems with heat and high water temperatures this past month but
we still were able to get two good reports from customers. One didn't turn out so good when
the water was low and the temperature high.
10/26/16 The river is in very good shape with lots of trout being caught. Stream levels are
currently fine and there is rain forecast about everyday. Large BWO hatches are taking place.
11/09/16 The stream levels are dropping but still very high, too high to wade safely in any
section of the river. These may be in good shape within two or three more days, but you will
just have to check. Remember, the season ends at the end of this month.
11/30/16 Today is the last day of the trout fishing season.
12/14/16 The regular trout season is over for the year. Let us help you plan your next trip.
Send us an email at:
12/28/16 Happy holidays. It won't be long before a new season begins.
01/25/17 The river is still closed to trout fishing, but it isn't to early to send us an email and let
us help you plan your next trip to the Flathead. Just let us know the dates you plan to fish.  
02/22/17 Just a note to tell you that we are waiting on your email to help you plan that 2017
fishing trip. We outfit several customers each year with flies and gear for it.
03/01/17 Remember, the main stem of the Flathead has a catch and release section that is
open. Send us an email and let us help you with that next fly fishing trip.
03/08/17 Cream and Red or blood midges, are hatching. Fish the larva and pupa rigged in
tandem. If it is cloudy and overcast, fish the Brown sculpin streamer.
04/19/17 We haven't received any recent reports from the catch and release section. Most
anglers fishing it are locals. The regular season opens soon. Send us an email and let us help
you plan that next fly fishing trip.
06/04/17 Runoff is underway and will likely last for two weeks or more. Keep checking back with
us and we will keep you informed. You can email us and let us help you plan that next fishing
trip to the Flathead.
06/21/17 The runoff is still well underway, with very high stream levels and dirty water. There is
a big snowpack this year but we do think it will be over soon. Keep checking back with us.
07/12/17 The river is in good shape with good levels and clear water. We are getting some
good reports from customers. There are Pale Morning and Evening duns, Callebaetis, Salmon
flies, Golden stones and little Yellow stones hatching. There Spotted and Green sedge caddis.
07/26/17 The lower river tailwater is getting into much better shape and some trout are being
caught. We have yet to receive any reports from the upper section above the lake. It is also in
much better condition and hatches should be going strong.
08/08/17 The river is in good shape in all sections. We are getting some good reports on a
regular basis. There are some good hatches going on.
08/23/17 Excellent conditions exist in all sections of the river. We received two good reports
form the past week. There are some good hatches taking place. Little Yellow stoneflies,
Spotted sedges, Green sedges, Western Ginger quills, PMDs, and more.
09/06/17 Conditions remain very good. We are receiving some good reports from all
sections. The hatches have slowed some, but some nice ones are still taking place.
09/27/17 We received one good report from customer fishing this past week. Hatches are
currently Blue-winged olives, Mahogany duns, Dark Red Quills, October Caddis, Spotted
sedges, and some Western Gingee Quills.
10/19/17 There are good reports coming in from the Kerr Dam tailwater of good numbers of
rainbows and some very large browns being caught on our Sculpin streamer patterns  When
discharge are reasonable, conditions are very good.
04/05/18 This section of the river has a catch and release season in the lower part of the
river. The regular trout season is over for the year. Let us help you plan your next trip. Send
us an email at:
05/05/18 The regular season will open soon but the catch and release section is open now.
The stream levels are high.
07/14/18 The Flathead River is getting in good condition with good stream levels and clear
water. We are getting some good reports.There are Pale Morning and Pale Evening duns,
Callebaetis, Salmonflies, Golden stoneflies and little Yellow stoneflies are hatching. There
Spotted and Green sedge caddis hatching.
07/28/18 The river is in good shape stream level wise and good numbers of trout are being
caught. There are still lots of hatches but they vary greatly with the section of the river you
may be fishing. Send us an email for a recommended fly list.
08/18/18 Good stream levels in all sections. We are getting good reports. Lots of hatches
including PMDs, Western Ginger Quills, spotted sedge caddis, green sedge caddis, little Yellow
stoneflies and others. Terrestrials are also working.
09/15/18 Conditions are very good in all sections of the river. There are good hatches taking
place and terrestrials are also working. This coming week should be a very good one.
02/15/19 Trout are being caught and release in the C & R section. Fish near the dam. The
water is warmer. Midges, creams and reds, are hatching. Rig the larva and pupa in tandem.
Winter stoneflies are hatching.
06/16/19 The river is still very high and stained or muddy from the Spring runoff. It will be
coming into good shape soon. Now is the time to get your flies and gear in order. Shoot us an
email and let us help.
07/02/19 The rver is down to a good level with good water color. Trout are being caught in
decent numbers. We received two good reports recently. There are some good hatches taking
08/02/19 The stream levels are a good bit below normal but in good shape. Trout are being
caught in good numbers. There are a lot of insects hatching and our terrestrials such as the
Japanese beetles, carpenter ants and sandwich hoppers are also working.
09/05/19 We received two good reports from customers fishing this past week. The stream
levels are in good shape and the weather and water temperature cooler.