Bighorn River Montana Fishing: Reports & Conditions
Planning a Bighorn River Montana fishing trip? Our bighorn river montana fishing reports track current water conditions, flows, hatches, and access notes so you can time your visit and fish with confidence.
Below is a complete Bighorn River Montana fishing guide covering techniques, hatches, species, access, and regulations. For live water data we reference USGS Water Data — always check current conditions before you go.
Bighorn River, Montana
Below Yellowtail Dam — Montana's premier tailwater and one of the most productive trout rivers in North America
The Bighorn River below Yellowtail Dam near Fort Smith, Montana is one of the most extraordinary trout fisheries on the continent — a wide, powerful tailwater that supports an estimated 3,000–5,000 trout per mile through its most productive sections. Consistent cold releases from Bighorn Lake maintain water temperatures in the ideal 52–58°F range year-round, creating a fishery of almost incomprehensible productivity in the arid plains of south-central Montana.
The Bighorn is fundamentally a float fishing river — wide, powerful current and limited wade access make a drift boat or raft not just preferable but often necessary for accessing the best water. The standard approach is to book a full-day guided float from Fort Smith or the nearby lodges, covering 13 miles of the most productive tailwater on the lower river. Wade fishing is possible from the Fort Smith access points and at specific gravel bar pullouts along the float.
The river's insect diversity is exceptional for a tailwater. Summer Trico spinner falls create extraordinary dry fly fishing — morning spinner falls so dense they cloud the air above the river, triggering simultaneous surface feeding from every trout in sight. PMDs, Caddis, and Sow Bug patterns all produce through the season, but the Trico hatch (late July through September) is the Bighorn's signature event and the reason anglers travel from across the country.
The Fort Smith area supports an excellent infrastructure of guides, lodges, and fly shops — the Bighorn Angler and Bighorn Fly and Tackle have documented the river's hatches for decades and are invaluable resources for planning your visit.
Fort Smith — Afterbay Dam Launch
Primary launch for float trips. Paved boat ramp at the Afterbay Dam below Yellowtail Dam. This is where the majority of guided floats begin. Wade fishing access at the ramp area.
13-Mile Access — Bighorn Recreation Area
Take-out and access point at the 13-mile mark below Fort Smith. Walk-wade access here and in the surrounding area. End point for the standard guide float.
Tribal Lands Access
Below the 13-mile access, the river flows through the Crow Indian Reservation. Tribal fishing permits required — available through authorized dealers. Excellent fishing with less pressure.
Rainbow Trout
Dominant species with exceptional population density. Averaging 14–18 inches throughout. Highly responsive to Trico and PMD dry fly patterns in summer. Strong fish in the Bighorn's powerful current.
Brown Trout
Numerous and large throughout. The Bighorn's browns are known for exceptional size — fish over 24 inches are encountered on most full-day floats. Most active during fall streamer fishing.
Trico spinner falls begin at first light — be on the water at dawn during July through September. The hatch is over by 9am.
Booking a guided float is strongly recommended for first-time Bighorn visitors. The river's complex current and fishing pressure make local knowledge invaluable.
Sow Bug and Scud patterns produce year-round in the Bighorn — even when no hatch is visible, sub-surface presentations with these patterns find willing fish.
September and October offer the best combination of Trico hatches, fall BWO emergences, and brown trout streamer fishing. The premier time to visit.
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