Gallatin River, Montana

Yellowstone National Park headwaters

The Gallatin rises in the park's northwest corner and US 191 picks it up inside Yellowstone, where about 25 miles of meadow river are fished on foot with a park permit rather than a Montana license. This is small water with rainbows, some cutthroat and whitefish, and it gets busier as the road leaves the park.

Gallatin Canyon and Big Sky

From the park boundary to the canyon mouth near Gallatin Gateway, US 191 stays beside the river and dozens of pullouts make it a drive, stop and fish river. The West Fork joins at Big Sky, and FWP estimates more than 1,400 rainbows over eight inches per mile from there to the canyon mouth. Fishing from boats is illegal from the park boundary all the way down to the East Gallatin confluence, so the canyon belongs to waders, and rafts here are for whitewater, not casting.

Gallatin Valley to Three Forks

Below the canyon the river slows through private ranch land past Gallatin Gateway, where this page's gauge sits, with access at FWP sites and bridges such as Williams Bridge, Shed's Bridge and Cameron Bridge. Below Manhattan, once the East Gallatin has joined, float fishing becomes legal and the lower river from Nixon Bridge down to the Missouri headwaters at Three Forks is brown trout water with logjams and a lot fewer anglers.

Rainbow and brown trout

Rainbows are the main fish in the canyon, browns increase steadily through the valley, and cutthroat, whitefish, scattered brook trout and a few grayling round out the river. Attractor dries and dry-dropper rigs cover the canyon pocket water; salmonflies come off between mid-June and early July depending on runoff, goldens follow into July, then caddis, PMDs and hoppers carry the summer.

Season and regulations

The Gallatin is a freestone with no dam. Outside Bozeman describes wadeable base flows of 300 to 400 cfs from mid-summer through spring and a runoff peak of 4,000 to 8,000 cfs in late May and June. This page treats 300 to 800 cfs at Gallatin Gateway as in range; above about 1,000 cfs the canyon is hard to wade and the water is usually off-color.

The river is open year-round except the stretch from Porcupine Creek Road to the West Fork, which opens the third Saturday in May and closes November 30. Central District limits apply: 3 trout daily, only one over 18 inches, only one a cutthroat, and all grayling released. No fishing from boats from the park boundary to the East Gallatin. A Montana license is required outside the park; the current Montana FWP regulations have the details.