Ruby River

Montana·Southwest Montana·45.34° N, 112.11° W

Flow

123 CFS

Ruby River above reservoir near Alder MT

Water Temp

73°F

Ruby River near Twin Bridges MT

Condition

Below Normal

Weather

68°F

Chance Rain Showers

near Alder

Insights

Flow

Low flows at 123 CFS

Fish are spooky. Lighten tippet and lengthen leaders.

Snowpack

Snowpack snowpack update

Snowpack data for Ruby River basin is limited right now. The June–July runoff forecast for Ruby R Reservoir Inflow is 63% of average.

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 Ruby is the small water in a neighborhood of giants. Tucked into the Ruby Valley between the more famous Beaverhead, Big Hole, and Madison, it runs roughly 30 to 40 miles of trout water from Ruby Dam near Alder down to Twin Bridges, where it folds into the Beaverhead just above the Jefferson headwaters. Below the dam it fishes as a partial tailwater — cold, brushy, willow-lined — and it is the brown trout that people drive over for. Most fish run 14 to 16 inches, but the Ruby holds a lot of 17 to 19 inchers and a genuine shot at a 20-plus on a river you can cover with a 5-weight and a pair of waders. It is technical small water: tight casts, wary fish, and hatches that reward matching over brute-force nymphing.

Practically, the Ruby is a wade-and-walk fishery, not a float. It is too small and brushy to float most of its length, so you work upstream through willow-lined runs, undercut banks, and meadow bends. Flows swing hard with irrigation — the Ruby bounces in and out of shape through the June-to-September growing season, and the number to watch is the release out of Ruby Dam (USGS 06020600, below the reservoir): 200 to 300 CFS is the sweet spot, it still fishes below 200, and above roughly 300 wading gets ugly and the banks blow out. Midges carry the winter and early season, a Mother's Day caddis emergence kicks off spring, PMDs and Yellow Sallies define June and July, and by late summer it is tricos, hoppers, and streamers stripped along the cut banks for the big browns. The upper river above the reservoir is a different animal — a true freestone small stream in the Beaverhead-Deerlodge National Forest holding rainbows, westslope cutthroat, browns, and a remnant Arctic grayling population, fished with a 3- or 4-weight.

The context that follows the Ruby everywhere is access. This is the river of the twelve-year stream-access fight: a media billionaire fenced off county bridge right-of-ways along Seyler Lane, Lewis Lane, and Duncan District Road, and the Public Land/Water Access Association sued Madison County to reopen them. The Montana Supreme Court reaffirmed the Stream Access Law in 2014, and a district court ultimately established a 47-foot public easement at the Seyler Lane bridge; the fight finally petered out around 2016-2017 in the public's favor. The upshot for anglers: once you are legally on the water at a bridge or fishing access site, you can fish through private land as long as you stay below the ordinary high-water mark. There are six-plus public access points between the dam and Twin Bridges, but bridge access here has been genuinely contested, so know where you are standing. Note the fall spawning closure — the dam-to-Alder-Bridge reach and the Sweetwater-confluence-to-reservoir reach shut down October 1 into spring to protect spawners.

Species

Brown Trout
Primary · Jun-Oct · 14-16" avg, many 17-19", 20"+
The defining fishery below the dam. Wild and resident year-round. Technical, wary fish tight to undercut banks and willows; the fall pre-spawn streamer bite is the trophy window (mind the October 1 spawning closure below the dam).
Rainbow Trout
Common · Jun-Sep · 10-16"
Wild and resident; more common the higher up the system you go and dominant in the upper freestone above the reservoir.
Westslope Cutthroat Trout
Present · Jul-Sep · 8-14"
Upper Ruby in the national forest — small-stream fish on the freestone reach above Ruby Reservoir.
Arctic Grayling
Present · Jul-Sep · 8-12"
A remnant fluvial grayling population in the upper Ruby — a notable native holdout. Handle with care and release quickly.
Mountain Whitefish
Common · Year-round · 10-16"
Native and common throughout; a useful winter nymphing target when the trout are dour.

Species	Abundance	Best Season	Size	Notes
Brown Trout	Primary	Jun-Oct	14-16" avg, many 17-19", 20"+	The defining fishery below the dam. Wild and resident year-round. Technical, wary fish tight to undercut banks and willows; the fall pre-spawn streamer bite is the trophy window (mind the October 1 spawning closure below the dam).
Rainbow Trout	Common	Jun-Sep	10-16"	Wild and resident; more common the higher up the system you go and dominant in the upper freestone above the reservoir.
Westslope Cutthroat Trout	Present	Jul-Sep	8-14"	Upper Ruby in the national forest — small-stream fish on the freestone reach above Ruby Reservoir.
Arctic Grayling	Present	Jul-Sep	8-12"	A remnant fluvial grayling population in the upper Ruby — a notable native holdout. Handle with care and release quickly.
Mountain Whitefish	Common	Year-round	10-16"	Native and common throughout; a useful winter nymphing target when the trout are dour.

Ideal wading flow150–300 CFS

Blow-out>350 CFS

Ideal water temp48–62°F

June-July is the classic dry-fly window: PMDs, Yellow Sallies, and caddis with pre-irrigation-peak clarity. September-October delivers the brown pre-spawn streamer bite and fall BWOs (mind the spawning closure below the dam). Spring (April-May) brings the Mother's Day caddis and BWO. Winter is midge nymphing on the tailwater for the committed. Watch the Ruby Dam release (06020600): 200-300 CFS is ideal, and above ~300 CFS wading becomes difficult and the banks blow out.

Sections

3 sections on this river

Lower Ruby (Alder / Silver Springs to Twin Bridges Confluence)

WadeBrown Trout · Rainbow Trout

A meadow river through arid agricultural land — willow banks, undercut bends, and classic brown-trout structure, warmer than the tailwater (mid-July water temps near 68°F have been recorded at the Twin Bridges gauge, so watch for afternoon warm-water stress). This is where the biggest brown trout live, and it contains the contested Seyler Lane, Lewis Lane, and Duncan District Road access bridges. Fish hoppers and terrestrials in late summer, streamers along the cut banks, and trico spinner falls at sunrise.

Best for: Trophy-class brown trout on small water — terrestrials, streamers, and trico spinners; the stream-access controversy bridges.

Ruby Tailwater (Ruby Dam to Silver Springs / Alder Bridge)

WadeBrown Trout · Rainbow Trout

The cold tailwater exiting Ruby Reservoir — brushy, willow-lined banks and undercut runs, the most reliably cold and technical water on the river. The strongest Yellow Sally emergence runs from the dam down to Silver Springs Bridge. Target wary brown trout with midge and PMD nymphs, Yellow Sally nymphs, streamers, and dries during the PMD and caddis windows. This reach is subject to the October 1 fall spawning closure (dam to Alder Bridge).

Best for: Technical small-water brown trout on nymphs and match-the-hatch dries; the river's best Yellow Sally water.

Upper Ruby (Gravelly/Ruby Mountains to Ruby Reservoir)

WadeCutthroat · Grayling · Brown Trout · Rainbow Trout

A true freestone small stream — pocket water, riffles, and small runs draining the Gravelly and Ruby mountain ranges, with the upper reach on Beaverhead-Deerlodge National Forest. Holds wild rainbow trout, westslope cutthroat trout, browns, and a remnant Arctic grayling population. Fish dry-dropper rigs and attractor dries (Adams, Royal Wulff, Stimulator, small Elk Hair Caddis) with a beadhead Pheasant Tail or Hare's Ear dropper on a 3- or 4-weight.

Best for: Low-pressure small-stream fishing for rainbow trout, westslope cutthroat trout, and remnant Arctic grayling; solitude on a light rod.

Regulations

Current fishing rules and restrictions

Managed as a general-regulation wild trout river in FWP Region 3 (Southwest). The signature Ruby rule is the fall spawning closure below Ruby Dam. No special fly-only or catch-and-release-only designation on the mainstem, but the Beaverhead/Big Hole/Ruby drainage sees repeated summer drought and hoot-owl closures — check FWP's restrictions page in season.

Fall spawning closure (effective October 1 into spring): Ruby Dam to Alder Bridge, and Sweetwater Creek confluence to the reservoir — closed to protect spawning brown and rainbow trout
Remaining reaches stay open under Montana's general season and standard Region 3 limits
Montana Stream Access Law: the public may use the river below the ordinary high-water mark, including through private land, once legally on the water at a bridge or access site
Watch for hoot-owl (afternoon) restrictions on the lower river in hot, low-water summers
Montana fishing license (conservation license plus fishing license) required

Sources have historically cited a September 1 spawning-closure date, but FWP's current rule closes the dam-to-Alder-Bridge and Sweetwater-to-reservoir reaches beginning October 1 (alongside the Big Hole and Beaverhead). The lower Ruby warms in late summer — water temps near 68°F (~19.8°C) have been recorded mid-July at the Twin Bridges gauge (06023000) — so watch for warm-water stress and potential hoot-owl restrictions; the tailwater below the dam stays coldest. Verify exact dates and boundaries in the current FWP regulations before fishing.

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

Access & Logistics

Getting there, fly shops, and lodging

Getting There

Twin Bridges, MT

30 min from Ennis, 45 min from Dillon, 1.5-2 hrs from Bozeman (BZN)

Fly Shops

Camping & Lodging

Cottonwood Campground on the upper river (Beaverhead-Deerlodge National Forest) and dispersed fishing-access sites along the lower valley; motels, cabins, and inns in Twin Bridges, plus larger services in Ennis and Dillon.

Six-plus public access points between Ruby Dam and Twin Bridges, including a public access right below the dam, Vigilante FAS, and the contested Seyler Lane, Lewis Lane, and Duncan District Road bridges — all now with confirmed public easements after the PLWA litigation. Stay below the ordinary high-water mark through private land. Bridge access here has a real history of dispute, so know where you are standing.

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

Beaverhead RiverMT

The premier Dillon-area tailwater below Clark Canyon Dam, famous for oversized, technical brown trout in tight, willow-lined water. Cold summer releases keep the upper river fishing all season, but heavy irrigation dewatering and repeated drought closures shape the lower river.

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.

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.