Fishing access to the Gallatin River is easy: The road runs alongside it much of the way from Yellowstone to Bozeman , and there are many pullouts—de facto fishing-access sites. There’s an official site at the Axtell Bridge, between Gallatin Gateway and Bozeman Hot Springs .
Fish don’t grow large in the cold waters of the upper Gallatin, but most anglers pull something from the riffling waters of this stretch. The West Fork comes in near Big Sky, and the combined waters flow through a canyon with exceptionally good fishing. Fishing from a boat is prohibited on the Gallatin.
The salmon flies hatch from late June through early July on the Gallatin, but there’s good fishing for brown and rainbow trout April through October.
Gallatin Riverguides (Hwy. 191, 0.5 mile south of the Big Sky turnoff, 406/995-2290, www.montanaflyfishing.com ) leads fishing trips year-round.
Lone Mountain Ranch  and 320 Ranch  also provide fishing guides, as does Wild Trout Outfitters (406/995-4895 or 800/423-4742, www.wildtroutoutfitters.com ). Guide rates vary widely depending on the sort of trip that’s arranged and how many anglers participate, but count on spending $325–425 for a day of private guided fishing. Costs per person go down dramatically when two or three people share a guide.