DIY Guide to Fly Fishing the Gallatin River in Montana

The Gallatin River is one of the top fly fishing destinations in Montana. It is located in the beautiful Gallatin Valley in south-central Montana.

Flowing north from Yellowstone National Park, the Gallatin River travels ~100 miles and then joins the Jefferson River and Madison River to form the Missouri River at the Missouri Headwaters State Park in Three Forks, Montana.

The main fish you can expect to catch on the Gallatin River are mainly Brown trout and Rainbow trout with the occasional Cutthroat trout. For the fly fishing enthusiast, the Gallatin River is a bucket list place to fish. 

The views in this part of Montana are some of the most scenic in the world. As the Gallatin River leaves Yellowstone National Park it winds through river brush and meadows before dropping into the canyon section south of Big Sky. Expect to see many types of wildlife and make sure you bring your camera to capture some of natures best scenes.

Gallatin River Map and Fishing Access Sites

Access to the Gallatin River is pretty easy as Gallatin Road / US 191 runs parallel to the river from the boundary of Yellowstone National Park all the way to Four Corners, Montana.  Access points vary from roadside pull-offs, bridge crossings, campgrounds and designated Montana Fishing Access Sites as shown on the map above.

Fishing the Gallatin River in Yellowstone National Park

One of the most accessible river in Yellowstone National Park, the Gallatin River is a beautiful stretch of water that has its headwaters at Gallatin Lake.

The upper Gallatin near Gallatin Lake is only accessible by backcountry hiking via the Bighorn Pass trail (see map above). The headwaters have a good population of cutthroat trout.

Flowing down the mountainside from the lake, the Gallatin tumbles and cascades its way to the broad valley of the Northwest quarter of the park. It makes an 11 mile run through the valley before flowing into Montana heading north toward Big Sky.

Gallatin River to Big Sky Montana

Heading into Montana, you can follow the Gallatin River where it flows down the mountain northward towards Big Sky. Fishing on this stretch of the Gallatin is said to be some of the best in Montana. The river here is accessible by numerous roadside pull-offs and a short walk across open sagebrush. 

Fishing the Gallatin Canyon

Below Big Sky, Montana the Gallatin enters a canyon where the water moves very quickly and is highly oxygenated. This area is known for an excellent Salmonfly hatch and a variety of other stoneflies hatching throughout July and August.

Best Place to Fish the Gallatin River

The best fly fishing is found along the banks of the Gallatin as it passes through the valley in Yellowstone. Fishing here requires minimal effort, as it follows Highway 191 for most of its run through the valley, and there are many pullouts and parking areas where you can step out of your car and be on the river bank within a few minutes walk.

The valley itself is largely small brush and grassland, so hiking a short way from your vehicle does not prove a challenge for most anglers. It’s a good idea to watch out for marshy areas as you walk though, and insect repellent is a must if it has rained recently.

Gallatin River Trout Fishing – What to Expect

The chief attraction to the Gallatin are the moderately sized rainbows and brown trout that call the river home. Most rainbows can grow as large as 12 inches, and browns range slightly larger at 14 inches or more.

The river can run narrow and shallow at various points through the valley, but it also has many deep pools and fast, shallow riffles that nearly always have some wily trout hiding in them.

Make sure your approach is slow and cautious, as the crystal clear waters and shallow depths increase the potential for spooking the fish.

Gallatin River Fishing Tips

The New Fly Fisher teams up with Dick Green of Bud Lilly’s Trout Shop in West Yellowstone, Montana to discuss how best to fly fish the Gallatin River.

Best Time to Fish the Gallatin River

The Gallatin River can be fished throughout the year. However, the best time to fish the Gallatin is mid-spring to late summer. You will find the long summer days of Montana to be very inviting with plenty of time on the river.

From March through September you can expect to find hatches of caddis, stoneflies (salmonflies and golden stonefiles), mayflies, spruce moths and midges. These various hatches lead to some of the best fly fishing on the planet.

Gallatin River Current Conditions

Gallatin River Fishing Reports

There are a number of area fly shops, outfitters, lodges and on-line retailers that publish Gallatin River fishing reports.  Listed below are a few to check out.

• The River’s Edge
• Montana Angler
• Bozeman Fly Supply
• Montana Troutfitters
• Gallatin River Guides

Gallatin River Hatches

Notable fly hatches on the Gallatin River include:

• March – Blue Wing Olives
• April – Blue Wing Olives, midges
• May – Caddis
• June – Golden Stones
• July – Yellow Sally stoneflies, Spruce Moths
• August – Spruce Moths
• September – midges

The best flies for Gallatin River are those that match the hatch!

Gear Recommendations

The upper reaches of the Gallatin River are relatively small and 7 1/2-foot 3-wt or 4-wt rod with a 9-foot 4X leader is all you need. For fishing the middle to lower reaches of the river a 9-foot 5-wt weight rod will be a better option to cover the large water and handle the wind.

Fishing Regulations

The Gallatin River outside Yellowstone National Park is open to fishing year-round.  The combined limit for brown and rainbow trout is five daily, and in possession, only one over 18 inches. All grayling and cutthroat trout must be released immediately.

A Montana fishing license is required. Options include a 2-day, 10-day or a season license and are available on-line from the Montana Department of Fish and Wildlife.

Fishing the Gallatin River inside Yellowstone National Park also requires a Yellowstone National Park fishing permit.  See our DIY Guide to Fly Fishing Yellowstone National Park for more information.

Trip Planning Tips

Travel to the Gallatin river is fairly simple. If you are travelling from out of state, you will want to fly into the city of Bozeman, Montana. From Bozeman it’s about an hour to Big Sky, Montana which puts you in the middle reaches of the river.

There are many campgrounds throughout this stretch of Montana a person can stay at. If you are looking for a hotel, it is common to find one that is locally owned. There are also regular hotel chains in and around the Bozeman area. If you prefer a luxurious accommodation you can find those near the Big Sky resort area.

Looking for more places to fish in Montana? Be sure to check out our Guide to the Best Fly Fishing In Montana