Guide to Fly Fishing on the Gallatin River MT (Maps, Flies and Technique)

Writing this, I can visualize so many trips to West (nickname for West Yellowstone). Landing in Bozeman and driving south along Highway 191 through the Gallatin Valley watching the river tumble along.   Usually, I would be on a schedule to meet friends, but I would stop and stare at the river, then inevitably rig up my fly rod.  The guys would understand that I’d be late.

Fly fishing on the Gallatin River is a “jumping-on river”, think of jumping-on a motorcycle after years of not riding.  Tossing a fly into those tumbling currents is an awakening to mountain rivers, reminding you again of the techniques and presentation needed to hook into mountain trout.

A Little About the Gallatin River

For many anglers visiting the West for the first time, the Gallatin River typifies their idea of a western river.  This is especially true if they view the river for the first time in the canyon along Highway 191.

The Gallatin River in this section south of Bozeman is a brawling, medium size freestone river.  Originating in the northwest corner of Yellowstone National Park at Gallatin Lake it flows generally north for 120 miles. The river was named by Meriwether Lewis after the Secretary of State Albert Gallatin. Source https://en.wikipedia.org/wiki/Gallatin_River

For the fly fisher, sections along 191 provide plentiful opportunities for the wading angler.  Predominately rainbows can be found in nice sizes, along with browns in the trophy sizes.

From June to August, whitewater rafters enjoy the run-off with rapids like the “Mad-Mile” drawing folks from around the country for a wet thrill.  Stop at the turn-off above to watch the action.

In the Park

In the small sliver of Montana contained within Yellowstone, the Gallatin is a beautiful stream running through meadows with braided currents.  The stream is friendly to wading with classic riffles, pools, and flats.  The undercut banks harbor browns, rainbows and cutthroat trout.

There are good populations of trout with an average size of 9 to 12 inches. 

This area doesn’t get much fishing pressure because the thought is that the populations are low, but don’t let the fool you.  Good numbers of trout can be caught here, just a little bit smaller in size compared to other areas.

Guide Pro Tip: I’ve often heard the quote “Teach a man to fish and you’ll feed him for a lifetime, teach him to fly fish and he’ll move to Montana” If you’re looking for a complete guide of where to fish in Montana you’ve got to read 👉 Where to Fly Fish in Montana

Taylor Fork Access – South of Big Sky

Just after the Gallatin leaves the park, Taylor Fork Creek enters the Gallatin.  From Taylor Fork south along 191 are multiple parking spots offering easy access.  It’s surprising how little pressure this area gets given the parking and easy wading.

I like this area because it provides ample casting room and a gentle current that is easy to read.  Check out my article on presentation to hone your casting and fly presentation.  Learn the Art of Presentation LINK 

A Little Secret – Taylor Fork

If you have a couple of hours to do some exploring, turn west onto Taylor Fork Rd.  A mile or so up the road is the Lower Wapiti Trailhead. Wapiti Creek enters the Taylor and provides a different view of the Gallatin River area as a higher gradient stream.  The perfect area to tie on a stimulator pattern to eager trout.  

Big Sky Area

Below Big Sky Resort the West Fork enters the river and the Gallatin starts to become a larger more powerful river that can be difficult to wade.  As the river changes the gradient increases as it enters the canyon section north of Big Sky. 

Access can be found in a couple of spots.  One spot with easier wading is just south of where the West Fork enters.  This spot will provide an hour or so of active fishing and will be popular during the salmon fly hatch in late June and early July. 

Another area with a little more river that’s convenient is a big sweeping bend just north of Big Sky 3-4 miles.  A two-track runs along the river making it easy to walk back to your vehicle after fishing.

Gallatin Forks

As the river hits the Gallatin Valley it slows and meanders into a braided river that is heavily influenced by water used for the surrounding farms.  The river is smaller here, but easy to read with runs, riffles and pools along with undercut banks.

During August this is an excellent section for terrestrials and during September and October, there are some great hatches of midge and blue wing olives.

When to Cast a Fly on the Gallatin?

I’ve spent the most time in this section of Montana in late summer into the fall.  I love the time after Labor Day when the crowds leave and the pace slows.  Because of this I’m a little bias, because I would trade a day of solitude in the mountains for a crowded day catching piles of fish.

After the runoff has slowed fishing will turn on, plan for late -June to July for eager fish looking to settle into patterns with hatches predictable in the mornings and evenings.  When fall approaches the terrestrials become more predominant.  (A perfect time to hang a nymph off the bend of a grasshopper pattern)

To answer when is best? For me late summer, but great fishing can be had during the peak vacation times, along with sunny winter days.

Guide Pro Tip: This river is slippery, wade with caution.  Outside of the park, you can use felt-soled wading boots, but I’d advise you to keep your felt in the bag and use rubber soles and a wading staff.  This is a delicate area and the spread of didymo and other invasives aren’t worth the risk.  Read more about felt sole bands in this article – Where are Felt Sole Boots Banned  

Why the Gallatin River is Perfect for Fly Fishing

The first words that come to mind are that the Gallatin River is a complete package.  Great access, lodging, guides with fly shops sprinkled from Bozeman to West Yellowstone.  Sections of the river don’t get much pressure if you’re willing to walk just a little farther.

What Streamflow is Best for Fishing the Gallatin?

Once the flow levels drop below 600 ft/second, fishing starts to normalize.  This usually happens in mid-June when the runoff is subsiding.

What Kind of Fish Can You Catch on the Gallatin River?

Rainbows, Brown Trout, Cutthroat, and Cutbows (hybrid between cutthroat and rainbows)

The rainbows seem to average 9 to 15 inches, but I’ve heard stories of bigger fish in the rapids area north of Big Sky approaching the Gateway area.

Browns grow big and are a little warier of taking a fly.  I believe as they get bigger they become night time feeders.  Still catches in the 12 to 18 inch size are the norm.

Cutthroat Trout, eager to take a fly early in the season tend to wise up later in the year after putting on some springtime fat.  Sizes range from

Favorite Flies for the Gallatin River

Salmon Fly – Size 6

When the hatch is on from late June to Early July it seems like the trout aren’t looking for anything else.  In the lower sections of the river where the Gallatin pours into the Missouri River headwaters, true trophies will be hooked on salmon flies.

Ants- Size 18

Mostly because I like the lesser crowded times on the Gallatin ants and hoppers will make up most of my fly box.  Easy to tie, but tough to see ants are a staple on the

Grasshoppers – Size 8

I’m haunted by meadows with hoppers jumping with every step closer to the river.  Late summer casting a grasshopper with a small midge nymph is a recipe for success.

Hatch Chart for the Gallatin River

Fly Name	Size	Start Date	End Date
Blue Winged Olive	18-22	April 1	October 15
Yellow Sally Stone	16	July 1	July 30
Pale Morning Dun	18-24	June 1	September 31
Golden Stone	6	July 1	July 20
Brown Caddis	14-16	July 20	July 30
Tan Caddis	12-16	April 25	May 25
Green Drake	14	July 10	July 31
Golden Stoneflies	10-16	June 1	July 31
Salmon flies	8-12	June 1	July 31
Midges	18-24	January 1	December 31
Terrestrials	6-12	July 25	October 31
Grasshoppers	8	July 1	September 15
Ants (Red, Black and Flying)	16-20	July 1	September 15

Fly Rod and Reel Setup for the Gallatin

Rod and Reel

The perfect setup is going to be a 9-foot, 6-weight it has the versatility to cast a light leader and tippet when needed, yet still has the punch for the bigger bugs and winds that the Gallatin River often gives to anglers.

My only comment about reels is to get something that has a reliable disc drag and balances with your rod. The little bit of extra strain on your wrist from a reel that isn’t balanced, will and discomfort after long days of fishing.

Leader and Tippet

Someone said “long and light” try to use leaders 9 feet or longer.  5X seems to be what I’ve settled with, but often I’ll tie on a 6X with a 7X tippet.

Guides and Fly Shops

Fly shops, guides, and lodges are scattered throughout this watershed.  I advise everyone to get a guide for the first day if you’re new to the area.  8 hours with a guide will add years to your learning curve.

• Gallatin River Guides in Big Sky is centrally located for fishing either north or south of Big Sky.  The perfect place to get a guide or gear up with local flies and a little “river wisdom” https://www.montanaflyfishing.com/
• The Rivers Edge (Simms Shop) in Bozeman is a newer shop, but with the backing of Simms.  Gear, Equipment and Guides are top-notch. https://theriversedge.com/
• Madison River Outfitters, If you make south to West Yellowstone, stopping at Madison River Outfitters is a requirement.  Great knowledgeable guides, flies and gear.  It’s like Christmas morning walking into this fly shop for a fly fisher.

Last Cast for the Gallatin

So many folks zip by this river chasing the big-name rivers like the Madison and Yellowstone.  Fly fishing is about slowing down, just a little bit and enjoying the journey.  I challenge you to stop at one of the spots I’ve called out and be a little late meeting up with your buddies.  Fishing along the Gallatin will give you some stories that will make those same buddies jealous.