Troutline

Beaverhead River

Montana·Southwest Montana·45.22° N, 112.66° W
Flow
652 CFS
Beaverhead River at Barretts MT
Water Temp
73°F
Beaverhead River at Twin Bridges MT
Condition
Above Normal
Weather
68°F
Chance Rain Showers
near Dillon

Insights

Flow
652 CFS — wading range
Solid water for fishing.
Pressure
Pressure dropping
Fish often move up to feed before a front.
Water Temp
Water 73°F — stress zone
Trout are oxygen-stressed. Fish dawn only, or pick a colder water — survival rates drop fast above 68°F.

The Beaverhead is the tailwater below Clark Canyon Dam near Dillon, and it earns its reputation as the place you go in Montana to hook the biggest brown trout of your life — and then watch it break you off in the willows. Cold, clear releases out of the reservoir keep the water fishing all summer, and the fish density is genuinely high: fly shops throw around 1,500-3,000 trout per mile in the upper reach, with a real percentage over 20 inches and browns that top 24. It fishes small even though it fishes big — the channel is often less than 70 feet bank to bank, tight against a double wall of willow, sweepers, and undercut banks.

None of that makes it easy. The upper river from Clark Canyon Dam down to Barretts Diversion is regularly called the most technical trout water in the state, and it earns it: big, educated browns, tiny nymphs, light tippet, fast twisting current, and constant boat traffic. It's primarily a nymphing game — scuds, sowbugs, midges, and PMD/Baetis nymphs fished deep and slow — though when the PMDs and caddis come off in June and July you get real dry-fly windows to fish sipping risers. Float is the default up top because the current is tough to wade above about 300 cfs; below Barretts the valley opens, the current slows, and wade fishing around Dillon becomes the better option. Expect crowds up top in June and July, and expect FWP's nonresident weekend float restrictions to shape where you can put a boat.

The lower river from Dillon toward Twin Bridges is a different animal — slower, warmer, chopped up by irrigation diversions, pipes, and fences that force portages, and drawn down hard by mid-summer withdrawals. Fewer people fish it, the trout are sparser but still big, and a lightweight raft or inflatable kayak beats a drift boat through the obstacles. Flows are the whole story: irrigation demand and reservoir management swing the river between fishable and either bony or blown out, and FWP has repeatedly imposed emergency and brown-trout-protection regulations on the drainage over the last few years. Dillon, Melrose, and Twin Bridges are the hubs, and there's a dense cluster of good fly shops that live and die by this river.

Species

  • Brown Trout
    Primary · Jun-Jul, Sep-Oct · 14-24"+

    The signature fish — more large browns than almost any Montana river, with 26"+ possible in the lower river. Catch-and-release only across the entire river (2022 drainage-wide rule). Fall pre-spawn streamer window is exceptional.

  • Rainbow Trout
    Common · Jun-Aug · 12-20"

    Wild and dense in the upper tailwater, regularly to 20". A conservative 1-fish limit applies; most anglers fish the river catch-and-release by convention.

  • Mountain Whitefish
    Common · Year-round · 8-16"

    Native and common throughout. Takes nymphs readily and makes a useful cold-season target.

Ideal wading flow250800 CFS
Blow-out>1,500 CFS
Ideal water temp4862°F

June-July is peak: PMDs, caddis, and Yellow Sallies bring the best dry-fly fishing and the highest fish activity (also the most crowds). September-October delivers fall browns, streamers, and BWOs with thinning pressure. March-May pre-runoff fishes midges and BWOs for big-fish potential. Winter is technical nymphing for whitefish and holdover trout.

Sections

3 sections on this river

Dillon to Twin Bridges (Lower Beaverhead)

FloatBrown Trout · Rainbow Trout

A slow, meandering flow through arid valley, chopped up by multiple diversion dams, pipes, jetties, and fences that force portages, and hit hard by irrigation drawdown that warms and thins the water by mid-summer. Fewer anglers, sparser but still-big brown trout, and trophy fish near Twin Bridges where the Beaverhead joins the Big Hole to form the Jefferson. A lightweight raft or inflatable kayak beats a drift boat through the obstacles.

Best for: Big brown trout for anglers willing to work; streamers and nymphs, solitude, low pressure.

Barretts to Dillon (Middle Beaverhead)

Wade & FloatBrown Trout · Rainbow Trout

The river drops into the valley — slower current, shallower water, and mostly private land, with excellent evening caddis. The same class of big brown trout and rainbow trout as the upper river but less finicky, making this the best wade-fishing water on the Beaverhead. Poindexter Slough, a spring-creek side channel worth its own trip, sits nearby. Chronic low water from irrigation withdrawals can limit floating. Watch for rattlesnakes on the banks in summer.

Best for: Wade fishing for brown trout and rainbow trout; dries during hatches, nymph rigs in the runs.

Clark Canyon Dam to Barretts (Upper Beaverhead)

FloatBrown Trout · Rainbow Trout

The trophy reach — a tight, twisting tailwater running through arid, willow-lined banks (the famous 'double wall of willow'). Cold, clear dam releases and fast current through constant bends, sweepers, and undercut banks hold big, selective brown trout and dense wild rainbow trout. Widely called the most technical trout water in Montana. Nymphing with scuds, sowbugs, midges, and Pheasant Tails is the core game, with dry-fly windows to risers during the PMD and caddis hatches. Access at Clark Canyon Dam, High Bridge, Henneberry, Pipe Organ Bridge, and Barretts.

Best for: Large, selective brown trout and rainbow trout on small nymphs and light tippet. Heavy June-July pressure.

Regulations

Current fishing rules and restrictions

Brown trout are catch-and-release only across the entire Beaverhead (drainage-wide protection adopted 2022). Managed as a wild trout fishery. Nonresident weekend float restrictions apply on designated sections in the May-Labor Day window, and the drainage sees repeated summer hoot-owl/drought closures.

  • Brown trout: catch-and-release ONLY, entire river
  • Rainbow trout: 1 fish daily and in possession; commonly fished C&R by convention
  • Artificial flies and lures with single-pointed hooks only (no bait, no treble hooks)
  • Clark Canyon Dam to Pipe Organ Bridge: open third Saturday in May through September 30
  • Below Pipe Organ Bridge: open the general season starting April 1
  • Nonresident float-fishing restricted on designated sections on weekends (third Saturday in May - Labor Day)

The Beaverhead/Big Hole/Ruby drainage has seen repeated emergency drought and temperature (hoot-owl) closures in recent low-water summers — check the FWP drought-closure page in July-August before fishing the lower river. A Montana fishing license is required; note the restricted-use river permit rules before floating.

Source: Montana Fish, Wildlife & Parks — 2026 Fishing Regulations. Regulations change annually — verify before fishing.

Access & Logistics

Getting there, fly shops, and lodging

Getting There

Dillon, MT

1 hr from Butte, 1.5-2 hrs from Bozeman (BZN), 2.5 hrs from Missoula

Fly Shops

Camping & Lodging

Camping at Clark Canyon Reservoir (Bureau of Reclamation) near the dam and at Beaverhead Rock State Park; motels in Dillon and Twin Bridges.

Access via Clark Canyon Dam, High Bridge FAS, Henneberry FAS, Pipe Organ Bridge, Grasshopper Creek, Corrals FAS, and Barretts on the upper river; Poindexter Slough FAS and the I-15 bridge at Dillon in the middle; Beaverhead Rock State Park and county bridges on the lower river down to the Big Hole confluence at Twin Bridges. Watch for rattlesnakes on the banks in summer.

Conditions data is live from public monitoring networks. Regulations change annually — always verify current rules with your state fish & wildlife agency before fishing.

More in Montana

View all 22 rivers

Southwest Montana

Big Hole RiverMT

The 'Last Best River' — 153 miles of classic Montana freestone from the Beaverhead Mountains through Wisdom, Wise River, and Glen to its confluence with the Beaverhead at Twin Bridges. Home to the lower 48's only fluvial Arctic grayling population.

East Gallatin RiverMT

Bozeman's spring-influenced backyard brown-trout stream — a small, weedy, serpentine meadow river that forms east of town and joins the West Gallatin near Manhattan. A separate drainage from the famous Gallatin canyon freestone: wade-only, technical, spring-creek-style fishing for wild browns, rainbows, and whitefish.

Gallatin RiverMT

The Gallatin runs through Yellowstone NP and the Gallatin Canyon along Highway 191 — wadeable freestone water for rainbows, browns, cutthroat, and whitefish, with a strong salmon fly hatch in late June and excellent post-runoff dry-fly fishing into October.

Jefferson RiverMT

A big, slow valley river running 77 miles from Twin Bridges to Three Forks, where it joins the Madison and Gallatin to form the Missouri. Modest trout numbers but genuinely large browns on streamers in fall — a spring-and-fall fishery plagued by late-summer irrigation dewatering and drought closures.

Madison RiverMT

The 'Fifty Mile Riffle' below Quake Lake is Montana's most famous wade-and-float water for wild rainbows and browns, with a strong salmon fly hatch in late June and consistent dry fly fishing into October.

Ruby RiverMT

The small water in the neighborhood of giants — a partial tailwater below Ruby Reservoir near Alder that runs brushy and cold down to Twin Bridges, famous for technical, willow-lined brown trout you cover with a 5-weight, and for the decade-long stream-access fight over its bridge crossings.

Yellowstone RiverMT

The longest undammed river in the lower 48 — 692 miles from headwaters inside Yellowstone NP through Paradise Valley to its confluence with the Missouri in North Dakota. The trout water runs roughly from Gardiner through Livingston and Big Timber, with the post-runoff salmon fly hatch in late June and consistent dry-fly fishing through October.

Other regions

Bighorn RiverMT

The Yellowtail Dam tailwater — 13 miles of fly fishing gold from the Afterbay to Two Leggins. 3,000-5,000 trout per mile, year-round consistent flows, and the West's most reliable sow bug and PMD fishery.

Bitterroot RiverMT

Western Montana's home water — 84 miles of cottonwood-bottomed valley fishing for wild rainbows, browns, and native westslope cutthroat. Famous for the March-April Skwala stonefly hatch and a long dry-fly season from spring through October.

Blackfoot RiverMT

The freestone river Norman Maclean made famous, rebuilt over 30 years of restoration into a genuinely wild fishery for westslope cutthroat, browns, and rainbows east of Missoula. No dam on the mainstem, a legendary June salmonfly hatch, and a boulder-strewn canyon corridor that fishes best from a drift boat.

Clark Fork RiverMT

Montana's longest river fishes like three waters in one — a skinny Superfund-recovery meadow stream up around Deer Lodge, a legitimate mid-size freestone through Missoula, and big float water down to St. Regis. Wild browns up top, 16-17" rainbows and cuttbows below town, and a marquee mid-September dry-fly window.

Flathead RiverMT

The big glacial-green valley river formed where the three forks meet near West Glacier, running through the Flathead Valley into Flathead Lake and continuing below Kerr Dam. A native westslope cutthroat dry-fly float up top, northern pike water down low.

Kootenai RiverMT

Montana's biggest tailwater, running cold and clear below Libby Dam in the state's far northwest corner. A float-and-dry-fly fishery for wild native redband rainbows, managed as a trophy reach with a 28-inch minimum below the dam.