The Gallatin is a blue ribbon river that originates in Yellowstone National Park. In its upper reaches, it flows through a spectacular alpine environment within the Gallatin Canyon where the fishing scenes from the movie A River Runs Through It were filmed. After exiting the canyon it enters the Gallatin Valley and becomes a meadow river lined with cottonwoods. The Gallatin is very close to Bozeman and our local Bozeman fishing guides know this river inside and out.
The Gallatin is a very picturesque river with crystal clear water and lots and lots of trout. The river is not known for trophy trout like some of the other larger rivers in the area, but the beauty of this river and its small intimate nature make this a favorite of many of our guests. Because of the very high trout density, this river often produces fast action and high catch rates.
The Gallatin is designated a wade fishing river only with the exception of the lower river. We sometimes use small rafts on the river in order to taxi from hot spot to hot spot where we get out and wade fish.
The river's character changes dramatically throughout four distinct areas: inside the park, the canyon, the Greater Gallatin Valley near Bozeman, and the lower terminus at its confluence with the Missouri.
Yellowstone National Park
The Gallatin begins as a small stream from a cirque lake several miles from HWY 191. Fishing is best lower down (closer to the highway) where it takes the characteristics of one of the Park's many quintessential meandering meadow streams. The stream parallels highway 191 from the meadow down offering easy access by car for several miles. Excellent wildlife including bears, moose, and deer are occasionally viewed along the banks.
Yellowstone Park Border to Spanish Creek (Gallatin Canyon)
Locals call this section the Gallatin Canyon. Beautiful gin clear pools surrounded by aromatic alpine forests; frequent moose crossings, and excellent hatches - no wonder they selected this portion for scenes in the movie "A River Runs Through It". The canyon is busy with fisherman throughout the year, but most noticeably once the RV traffic arrives in July and August. Excellent nymphing and the surprise of a solid mayfly hatch beginning mid-spring (baetis) or post run-off (PMD's) provides fantastic dry fly opportunities for aggressive rainbows. Fortunate anglers may experience thick hatches of salmon flies and golden stones if high water doesn't blow these hatches out. Every few years, cyclic infestations of terrestrial Spruce Moths also bring fanatical trout to the surface late July through mid August while the moths dive bomb from overhanging spruce bows toward the bright reflection of the river's surface (much like moths dive bombing your porch light). Trout literally line up and open their mouths for a gravy train of moths, which closely resemble size 12-14 tan caddis.
Spanish Creek to Manhattan
The river suddenly changes character as it exits the alpine canyon and flows through the wide agricultural valley, also known as the Greater Gallatin Valley, which is home to nearby Bozeman, Montana. Hay fields and cottonwoods dominate the shoreline of the river as it braids repeatedly forming riffles, islands, and long deep pools. Wading access is available at several bridges and FAS locations roughly every 8 miles. This section fishes consistently well although agricultural dewatering above the village of Gallatin Gateway limits the river's potential. The average size of the trout increases and browns become more prominent. Trout numbers drop and fish tend to be more spread out depending on the volume of flow and available holding water. Midges, mayflies, caddis, terrestrials, and tricos (lower down) are the most prominent insects observed in this region.
Manhattan - Headwaters State Park
The lower Gallatin River forms when the East and West (main) Gallatin join forces at the Gallatin Forks near Manhattan. It terminates at the confluence of the mighty Missouri River alongside the Madison and Jefferson Rivers near the town of Three Forks, Montana. The lower Gallatin River does have some large trout that make there way up from the Missouri river. Float fishing from a drift boat is allowed on the last 12 miles and this section of the river is a great option in the fall. Although the fish counts are lower than farther upstream, the potential for trophy fish make it an interesting option in October. Midges, mayflies, caddis, tricos, and terrestrials are the prominent insects. Sculpin, crayfish and streamer tactics are also excellent options when the fish are willing. Catch rates usually aren't off the charts this far down but the average size of large fish makes for an agreeable trade-off.
Fishing the Gallatin by time of year
An angler could find remarkably different happenings on the four different sections of the Gallatin on any given day. Thus, these guidelines characterize the Gallatin above the town of Gallatin Gateway and into the Yellowstone National Park, which is by far the most popular stretch.
Spring (March - May)
The spring fishing on the Gallatin can be fickle and is really dependent on weather. Look for warm sunny days in March to energize the fish between 11am and 3pm. Girdle bugs, little golden stones, midges, baetis nymphs, attractor nymphs, worms, and eggs are all productive. Warm overcast days are excellent for baetis hatches usually starting in mid-April. Be sure to bring a variety of size 18 baetis nymphs, emergers, and duns. My favorite days are warm fronts later in spring, which bring light drizzle and temperatures in the mid to high 50's. These days typically bring consistent BWO hatches in the afternoon and exciting dry fly fishing to follow. Avoid fishing during or just after cold fronts.
Run off (Late May - Late June)
The Gallatin drains a lot of real estate, much of which is covered by deep snow pack throughout the winter. The river is best left for whitewater enthusiasts at this time. If you have the itch and are watching the gauges, an adventurous angler can successfully pull fish with large heavy stonefly nymphs and San Juan Worms fished tight to boulders and side eddies after the river crests and begins to subside. You'll have better success if you wait for the water clarity to exceed 16".
Summer (July - September)
Fishing the Gallatin is excellent this time of year, with the best fishing following the subsiding run-off. Hatches of salmon flies and golden stones occur immediately after run-off begins to subside. Casting size 6-8 Rogue Stone dry flies around slack water created by boulders and eddies is quite productive. The stone fly hatches will typically be concentrated in a stretch of a few miles. Be sure to move up and down the river when you're around the hatch in order to fish different phases of the life cycle. Fish can become gorged on the big bug, but the hatch isn't so dense like other western rivers. Move if fish aren't cooperating in one spot and you see lots of spent shucks along the bank. Hatches of caddis and PMD's are thick in July and follow the stones. Anglers will find caddis on sunny days and thick PMD's on cloudy afternoons. Bring an assortment of attractor nymphs, PMD's (nymphs, emergers and dries), caddis (larvae, pupae, emergers, and dries), and San Juan Worms (if a thunderstorm recently blew sediment into the river). One last thought regarding the major hatches - western drakes are sometimes reported in the Yellowstone Park section of the Gallatin in July.
Attractor dries work great once the main hatches begin to draw to a finish around mid July. Fishing the canyon until dark using Elk Hair Caddis and attractor dries can be very memorable. By mid July, the RV's have arrived in full force and begin to pressure many of the beautiful holes within sight of the road. This is a good time to tippet down and size down to 16 and 18's with your nymphs. Don't be shy about walking away from the highway access points, fishing pocket water, and throwing terrestrial dries in the afternoon.
The Gallatin is frequently blown out with silt in the summer time following large thunderstorms. Clean water is sometimes located in the Park above many of the lower side streams, however occasionally this section becomes off color too. Save your time and fish elsewhere when visibility is zero. The Gallatin usually takes approximately 2 or 4 days to clear depending on the side stream that blew. Fishing can be quite good once the river begins to "green up".
A word of caution; Highway 191 is one of the most deadly highways in the country. Anglers should provide plenty of warning with turn signals while moving between roadside pull-offs. The heavy trucks commuting this highway will appreciate your safe driving.
Fall (October - November)
Fish can be spooky in the low gin clear water typical of late Fall on the Gallatin. Many anglers are focused on the excellent fishing opportunities occurring elsewhere on larger rivers in the region; specifically for big Browns moving to their spawning areas. Other local anglers simply hang up their fly rods in lieu of elk and pheasant season. Minimal crowds and consistent Baetis hatches on cloudy afternoons can be quite fun.
Winter (December - March)
Most of the Gallatin is pretty slow in the dead of winter. Ice can choke the river starting in December with one exception; high quality winter fishing takes place just downstream of the Big Sky junction along Highway 191. Several springs warm the river and keep it ice free while also congregating fish. Typical winter fishing strategies apply, such as fishing during the warmest hours on sunny days with midge imitations. The effect of these springs is no secret though, so take a number and wait for the best holding water.