James Marsh fishing Big Gunpowder Falls River
Big Gunpowder Falls River
Copyright 2021 James Marsh
Fly Fishing Big Gunpowder Falls River,
The Big Gunpowder River starts in Pennsylvania and
flows through Maryland into Cheaspeake Bay. The
Prettyboy Reservoir Dam releases 55 degree water
year-round, making it one of the better tailwaters in the
East. The river runs through the beautiful Gunpowder
Falls State Park.

A self-sustaining brown trout fishery exist in the seven
mile long tailwater section of Gunpowder Falls River
below Prettyboy Reservoir. This section is not stocked.
There are catch and release regulations for the upper
seven miles of the river, or from the dam to Blue Mount

Brown trout make up almost all of the population of trout
but there are a few rainbow and brook trout. Trout are
stocked below the catch and release section of the river.
Most of the stream consists of long pools with short
section of riffles joining them. There is one section of
rapids below Route One called the "Pot Rocks" because
of the deep holes in the stream.

Little Falls River is one of the larger tributaries of the
main Gunpowder River. There are several other tributary
streams. Put and take trout fishing is available on the
Lower Big Gunpowder Falls River.

Fly Fishing Guide to the Big Gunpowder Falls River
The best method to use to consistently catch the brown
trout in Big Gunpowder Falls River is nymph fishing. he
best fishing is in the catch and release section or the first
seven miles below the dam. The area below the seven
mile catch and release section, is managed as a "trophy
trout" section. Only two trout over 16 inches can be
taken. It also provides very good fishing. There are
several designated trails that access the river.

Low discharges from Prettyboy Reservoir can sometimes
make fishing tough sometimes in the Catch and Release
Section but the fishing is generally good year-round. The
stream can become crowded at times during the spring
season, but it is usually the weekends that sees the most

As mentioned in the introduction, most of the trout are
brown trout. Large brown trout rarely hit a dry fly. There
are rare occasions it does happen but your odds are far
better fishing a wet fly or nymph. The bottom is fairly level
in most sections and strike indicators work okay most of
the time. Double or tandem fly rigs also seem to work well
on the Big Gunpowder Falls River.

It is far better to use an imitation of an aquatic insect that
is near its time to hatch than generic nymphs. Specific
imitations of the mayfly nymphs that are most available
for the trout to eat are far more productive than the
generic flies. The wild brown trout are usually very
Type of Stream

Brown Trout (wild)
Rainbow Trout (stocked)
Brook Trout (stocked)


Northern Maryland

Nearest Towns



Non-Resident License
State of Maryland

National Weather Service Link

Dam Discharges:
Parkton USGS Real-time Water

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Big Gunpowder Falls
River, Maryland
Fly fishing Big Gunpowder Falls River is good
all year.
Spring provides the best opportunity to catch
a trout on a dry fly.
The summer season can have low
discharges from the Prettyboy Dam, making
the fishing tough.
Big Gunpowder Falls River Hatches:
Our information on aquatic insects is based on
our stream samples of larvae and nymphs, not
guess work. We base fly suggestions on
imitating the most plentiful and most available
insects and other foods at the particular time
you are fishing. Unlike the generic fly shop
trout flies, we have specific imitations of all the
insects in the Big Gunpowder River and in all
stages of life that are applicable to fishing. If
you want to fish better, more realistic trout flies,
have a much higher degree of success, give
us a call.  We not only will help you with
selections, you will learn why, after trying
Perfect Flies, 92% of the thousands of our
customers will use nothing else.

The Big Gunpowder Falls River flows through a
lot of limestone rock creating a good pH level.
This means there are a lot of aquatic insects
available for the trout to eat. Little Winter
Stoneflies are the first insects to hatch. Midges
hatch throughout the year and provide the
best opportunity to catch trout during the

From about the middle of March through the
month of May, Blue-winged Olives are the main
aquatic insect that hatch. These are mostly
baetis species. They hatch again starting
about the first of August and lasting until near
October. Some of these are small BWOs and
little BWOs. They will vary from hook sizes 16
down to a size 24.

Around the middle of March Little Black
Caddisflies, or Grannom Caddis, start hatching
along with some Blue Quill mayflies. The
caddis hatch last just over a month. The Blue
Quills can last almost two months. Little Brown
Stoneflies will start hatching about the middle
of March and last over a month.
Hatches, Continued
The first of May will also start the first Green
Sedge hatch and the Short-horned Sedge
hatch. Both hatches last about a month. Most
of the caddisflies will be Cinnamon and
Spotted Sedges. They hatch from mid-May
until the end of August and provide some of
the best opportunities to catch trout on the dry

Sulphurs start the middle of May and can last
for a month and a half. This is one of the Big
Gunpowder Falls River's best and most
consistent hatches.

By the middle of June, terrestrial insects can
become important. Ants, beetles and grass
hoppers imitations will catch trout. Don't forget
the streamer flies. They can produce anytime
of the year, especially early and late in the day
or when the water is stained from heavy rains.

It is far better to select the flies you need with
you from the hatch chart than to use generic
or attractor flies. We have the World's best
trout flies that will match the hatch any day of
the year on the Big Gunpowder Falls tailwater.
If you haven't tried them already, we
encourage you to do so.

The Hendrickson hatch starts about the middle
of April. The hatch will last about a month.
By the first of May, you may find some large
Eastern Green Drakes and even a few Brown
Drakes. They  hatch for about three weeks.
There are a few Eastern Pale Evening Duns
that start near the end of April. The American
March Browns and the Light Cahills both start
hatching around the middle of May. Both of
these will hatch for almost two months.
Streamers and wet flies also work great for the
larger brown trout at certain times. The river
has plenty of minnow, baitfish and sculpin and
imitations of them are productive early and late
in the day, or during heavy cloud cover. They
can also be effective when the water has some
color or tint to it.

The brown trout spawn during the fall. The
spawning activity causes them to loose a lot of
their normal caution. They are out and about
moving around rather than hidden up under a
rock or undercut bank. You can often spot
them moving upstream during the pre-spawn
period. Large nymphs and streamer work great
at this time. We don't recommend fishing for
them on their redds.
Guide, continued
You should always obtain the current stream
flow data prior to fishing the Big Gunpowder
Falls River. You should also exercise caution
when fishing the tailwater. It is subject to
suddenly rise. The stream levels affect the
fishing greatly. You cannot wade if there is too
much water being released. During periods of
low flows, the trout can become easy to spook,
making fishing much tougher. It does provide
more opportunity to sight fish but all in all, low
water levels are difficult to fish.
James Marsh fishing Big Gunpowder Falls River
Angie Marsh fishing Big Gunpowder Falls River
Big Gunpowder Falls River
Big Gunpowder Falls River
Thumbnails: Click to enlarge
Thumbnails: Click to enlarge
Autumn is the time the brown trout spawn and
loose a lot of their normal caution.
Trout can be caught during the winter. Midge
fishing is usually good.
Fishing Report Updated 02/14/2021
(Bottom Of Page)
Big Gunpowder Falls River Fishing Report - 02/14/2021
The discharges and stream levels are a good bit below a normal level. There are some
good hatches taking place. Trout are still being caught by our customers.
Stream Conditions:

7 Day Weather Forecast:
(click here to see more detailed weather information}

Recommended Trout Flies:
Rate: 53.5 cfs
Level: 1.74 ft
Clarity: clear
USGS Real-Time Stream Flow Data Near Parktown MD
Midges: Blood (Red), sizes 20/22, larva, pupa and adults
Midges: Light Green, size 20/22, larva, pupa and adults
Midges: Cream, size 20/22, larva pupa and adults
Brown Sculpin and White Belly Sculpin, size 6
Blue-winged Olives: size 18 and 16, nymph, emergers, duns and spinners
Aquatic Worms, size 12, pink, red, and others.
Winter Stoneflies, size 16/18, nymphs and adults
Black Flies, size 18/20, larva, pupa and adults
Strategies, Techniques and Tips:
Blue-winged Olives are hatching.
The Brown Sculpin and White belly sculpin are great flies to use throughout the year.
We still think a good strategy is to fish a tandem Midge rig under a small strike indicator
with the midge lava as the bottom fly and the midge pupa as the top fly. Fish the adult
midge only when you observe trout feeding on the surface
Winter stoneflies are hatching.
Aquatic worms are working.
Black flies are hatching.
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.

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