Beginning in Yellowstone National Park and winding southward past Big Sky into the Gallatin Valley near Bozeman, eventually arriving in Three Forks to join the Madison and Jefferson Rivers to form the Missouri River, the Gallatin makes a great run through southwest Montana and it fishes well from top to bottom. The locals call her 'The Gally', and this river may be one of the most accessible streams in all of Montana. From a meandering stream in YNP, to a hard charging mid-sized river in the canyon section, to a larger floatable river in the lower portion, the Gallatin has great public access all along the way.
In the Gallatin Canyon near Big Sky you may have to contend with whitewater rafters and kayakers as much as trout, but above and below are generally quiet and allow ample room to find a few nice rainbow and brown trout. The closer you get to the headwaters of the Missouri the larger the fish tend to be, and the more open country you'll get to see along the way as you are on the Gallatin Valley floor.
Our sister flyshop Gallatin River Guides, located within a lob wedge of the river's edge, can take care of all your fly, tackle and informational needs when you're in the Big Sky area. Pat Straub and his crew at the shop know their stuff and sell only the best brands to their anglers, including Simms, Winston, Sage and Patagonia.
Fishing Seasons and Techniques
The Gallatin is a year round wade fishery for both local and traveling anglers. You'll find folks out working the water most days in winter, especially in March as temperatures warm a bit and Big Sky skiers look for a break from the slopes and head out to catch some trout. April and May offer some decent mayfly and midge hatches, but the Gallatin shows it's true colors after run-off has subsided in mid to late June.
Because of it's generally quick pace and smaller fish, matching the hatch is not as important on a river like the Gallatin as a general rule of thumb. A well presented generic pattern (stimulators, parachute adams, humpys, royal wulffs), will get you plenty of attention on most days. The stonefly hatches in June and July - salmonfly, golden stones and yellow sallies - can be phenomenal and there's just nothing like having a fly as long as your ring finger devoured by a trout to get your blood pumping.
Green drakes and pale morning duns will fill out the mayfly hatches for the summer months, along with early morning trico emergences and afternoon caddis flights. After that it's hoppers, ants and beetles to get the trout to look skyward, with a nice baetis hatch in Sept and October to round out the season. Tugging streamers in the fall can be very effective, especially below the canyon where some big brown trout lurk and get feisty as they prepare to spawn.
The Gallatin River is another Montana bucket list water that deserves your attention, and serves very well as a leg of a Trout Tour through the greater Yellowstone area and beyond.