The Gallatin River is known for its rainbow trout, cutthroat trout and brown trout. It starts in Yellowstone National Park and flows north for 100 miles to the confluence with the Missouri River. This yearround river runs through wide open meadows and canyons.
South of Big Sky, the Gallatin River is a narrow stream. Downstream of Big Sky after the Taylor Fork confluence, the river increases in flow considerably and enters 20 miles of Gallatin Canyon. The canyon is pretty rocky with steep sides, but SR191 provides good access points. This is one of the more popular stretches.
The access for fly fishing on the Gallatin River is provided by SR191 in the upper sections above Belgrade and then by SR90 below Belgrade.
Overall, Gallatin River is the 11th most popular fly fishing river of all 21 fly fishing spots in Montana.