Bighorn River

Fishable

Montana

Current Flow1,740 CFS Stable
Guides30
Sections2

Current Conditions

1,740CFSStable over 24hr

The Bighorn River is running at 1,740 CFS — fishable but higher than ideal. Nymph rigs will outfish dries today. Streamers may produce.

Last updated: Mar 30, 2026, 10:15 AM from USGS gauge 06287000 (Bighorn River near St. Xavier)

7-Day Flow Trend

Optimal Fishable Marginal Blown Out

Flow thresholds: Optimal 25004000 CFS | Fishable to 6000 CFS | Marginal to 8000 CFS

About the Bighorn River

The Bighorn below Yellowtail Dam near Fort Smith is one of the most productive tailwaters in the country. Cold, clear releases support incredible trout densities — 5,000+ trout per mile in the upper reach — with fish averaging 15-18 inches.

Hatch Chart

InsectJanFebMarAprMayJunJulAugSepOctNovDec
Midge
Zebra Midge #18-22
Blue-Winged Olive
BWO Parachute #18
Pale Morning Dun
PMD Sparkle Dun #16
Caddis
Elk Hair Caddis #14-16
Trico
Trico Spinner #20-22
Major Moderate MinorCurrent month highlighted

Active Hatches — March

Midge(major)

Patterns: Zebra Midge #18-22, Griffith's Gnat #18, WD-40 #20

Blue-Winged Olive(major)

Patterns: BWO Parachute #18, Sparkle Dun #18, RS2 #20

River Sections

Afterbay Dam to Bighorn Access

wade/float access
Fishable

1,740 CFS

The first 3 miles below the dam — highest trout densities. Excellent wading and drift boat fishing.

Bighorn Access to Two Leggins

float access
Fishable

1,740 CFS

Broader water with deeper runs. Great float section with fewer anglers than the upper stretch.

Guides on the Bighorn River(30)

These fishing guides list the Bighorn River as one of their home waters.

View all 30 guides in Montana

Frequently Asked Questions

What is the best time to fish the Bighorn River?+

The Bighorn River fishes well from spring through fall. Peak dry fly season is typically June through September. The best hatches occur during summer months with PMDs and caddis. Fall brings excellent streamer fishing and fewer crowds.

What flies work on the Bighorn River in March?+

In March, the Bighorn River sees Midge, Blue-Winged Olive activity. Top patterns include Zebra Midge #18-22, BWO Parachute #18. Always carry a selection of nymphs as well.

How many fishing guides operate on the Bighorn River?+

Outguided lists 30 fishing guides who operate on the Bighorn River. These guides offer local knowledge of hatches, access points, and current conditions that can significantly improve your experience.

What is the current flow on the Bighorn River?+

The Bighorn River's flow data is updated every 30 minutes from USGS gauge stations. Check the top of this page for current CFS readings, fishability status, and a 7-day flow trend chart. Optimal fishing flows are 2500–4000 CFS.

What fish species are in the Bighorn River?+

The Bighorn River primarily holds wild brown trout and rainbow trout. Cutthroat trout may also be present in some sections. Fish sizes vary by section, with tailwater reaches typically holding larger fish.

Quick Conditions

StatusFishable
Flow1,740 CFS
Trend Stable
Guides30

Fishability Thresholds

Optimal25004000 CFS
Fishableto 6000 CFS
Marginalto 8000 CFS
Blown Out8000+ CFS

USGS Gauges

Bighorn River near St. Xavier

Station #06287000