Jefferson River
Twin Bridges to Three Forks
SW Montana, USA
Open live forecast →Target species: Brown and Rainbow.
Stream gauge: 06026500. Flow and water temperature update on every refresh.
Weekly AI Outlook as of 06/05/26
At 2520 cfs and 59.9°F, the Jefferson is running high but fishable with solid PMD and caddis potential. This week's temperature swings — highs near 80°F dropping to the 50s with rain Saturday — will trigger strong evening hatches before conditions tighten. Focus on the deeper channels between braids where fish concentrate during higher flows, and prepare for excellent rise fishing if you time the evening emergence windows right.
- Flow: 2520 cfs — elevated but manageable. Fish the main channels between braids where current concentrates trout during higher water.
- Hatches: PMDs and caddis primed with 59.9°F water. Evening emergence peaks likely Thursday-Friday before weekend cooling.
- Water Temp: 59.9°F — perfect for sustained PMD activity. Caddis emergence threshold crossed, expect strong evening rises.
- Best Window: 6-8pm evenings through Friday. Saturday's rain and 50°F high will shut down surface activity temporarily.
Generated weekly from live USGS gauge readings, weather forecasts, and recent fly shop reports. Updates Friday mornings.
About this Water
- Freestone
- Best months: May–Oct, peak Sept–Oct
Formed at Twin Bridges by the confluence of the Beaverhead and Big Hole rivers, the Jefferson flows north through a broad valley to meet the Madison and Gallatin at Three Forks — forming the Missouri River. It's a wide, warm-tending freestone river with a reputation for large brown trout in its deeper bends and log-jam pools. While it lacks the glamour of its famous neighbors, the Jefferson offers exceptional float fishing for anglers willing to work for their fish.
The Jefferson's confluence with the Madison and Gallatin at Three Forks forms the official headwaters of the Missouri River — three of Montana's finest trout rivers joining at a historically significant location.
January Outlook
January on the Jefferson is cold and slow. The valley floor freezes hard and fishing is not practical for most of the river. Some midge activity in the deeper pools near Twin Bridges on the warmest days. Not a recommended winter destination.
Productive Patterns
- Zebra Midge
- RS2
- WD-40
Tips
The Jefferson is better visited in warmer months. If you must fish in January, target the deep bends near Twin Bridges on the mildest days available. The river is cold and often partially iced.
Water Notes
600–1,200 cfs. Valley sections may freeze partially. Water 32–40°F. Very limited fishing potential.
February Outlook
February remains off-season. The river is cold and fishing is limited to brief midge activity on the warmest afternoons. The Jefferson's season begins in earnest in May.
Productive Patterns
- Zebra Midge
- RS2
- Midge Larva
Tips
March-April bring more realistic fishing. February is best spent planning the May-October season when this underrated river is excellent.
Water Notes
700–1,300 cfs. Cold and often icy in the valley. Water 34–44°F.
March Outlook
March sees the Jefferson beginning to stir. Midge and first BWO activity on warm afternoons. The river clears quickly and large brown trout become visible in the deep bends. Not prime yet but improving.
Productive Patterns
- Sparkle Dun #18
- Zebra Midge
- RS2
- Pheasant Tail
Tips
March is the warm-up month on the Jefferson. Fish the deeper bends near Waterloo and Silver Star. BWO activity 11am–2pm on warm afternoons can be surprisingly good.
Water Notes
800–1,500 cfs building toward spring. Water 40–50°F. River warming and accessible.
April Outlook
The Jefferson hits early runoff in April. Wide valley braids can blow out but inside channels often remain fishable. Streamers through the deeper bends produce large browns in colored water.
Productive Patterns
- Streamer
- Jig Nymph
- Woolly Bugger
- Elk Hair Caddis (late April)
Tips
Monitor flows at Twin Bridges gauge. Inside channels and side braids clear first. When the main channel blows, fish the edges with large streamers. Late April can produce excellent caddis action if flows cooperate.
Water Notes
1,500–5,000 cfs. Variable clarity. Jefferson clears faster than most valley rivers due to braided character.
May Outlook
The Jefferson warms earlier than higher-elevation rivers. PMD and Caddis hatches arrive in May. Good wade and float fishing for brown and rainbow trout in the wide valley reach.
Productive Patterns
- Elk Hair Caddis
- PMD Sparkle Dun
- Streamer
- Copper John
Tips
The Jefferson is underrated in May — fish are active and pressure is low. Float from Twin Bridges to Waterloo. Side channels hold fish in high flows.
Water Notes
1,500–4,000 cfs with spring runoff. Jefferson runs high and silty from spring runoff from Big Hole and Beaverhead. Best in low-flow windows between rain events.
June Outlook
Caddis and PMD hatches. The Jefferson's wide braided valley creates outstanding evening rise fishing when conditions are right. Brown trout are the primary quarry.
Productive Patterns
- Elk Hair Caddis
- PMD
- Golden Stone
- Hopper (late June)
Tips
The Jefferson is a leisurely float river. Camp at the river accesses and fish evenings when hatches peak. The braided channel fish concentrate in the seams between channels.
Water Notes
1,000–2,500 cfs. Flows dropping and clearing. Water 56–64°F.
July Outlook
Prime hopper and caddis season. The Jefferson's warmth and width creates ideal hopper habitat. Fish the cut banks and seams between braids for large browns.
Productive Patterns
- Dave's Hopper
- Elk Hair Caddis
- Chubby Chernobyl
- Streamer
Tips
Float the Jefferson in July for a relaxed, uncrowded experience. Large brown trout in the 18-24 inch range inhabit the deep bends and log jams. Fish can handle the float traffic better than higher-altitude rivers.
Water Notes
700–1,500 cfs. Warm water — fish early morning. Water 66–72°F. Fish in shaded areas midday.
August Outlook
The Jefferson runs warm in August — focus on early morning and evening sessions near spring creek tributaries and shaded bends.
Productive Patterns
- Dave's Hopper
- Trico Spinner (morning)
- Caddis (evening)
- Streamer
Tips
August can see the Jefferson exceeding optimal trout temperatures. Focus within 2 miles of cold spring tributaries where fish concentrate. Early morning Trico hatches and late evening sessions are the most productive.
Water Notes
500–1,000 cfs. Water can exceed 68°F midday. Fish pre-8am and post-7pm for best action.
September Outlook
Fall conditions restore excellent fishing. Brown trout are increasingly active. BWO hatches and streamer fishing improve through September.
Productive Patterns
- Blue Winged Olive
- Streamer
- Hopper
- Elk Hair Caddis
Tips
September is the Jefferson at its best for large fish. Cooling water triggers aggressive feeding. The braided lower river near Three Forks produces some very large fish.
Water Notes
400–800 cfs. Cooling and clearing. Water 54–62°F. Prime fall conditions.
October Outlook
Excellent brown trout fishing. Pre-spawn browns are aggressive to streamers and large attractors. One of the better late-season destinations in SW Montana.
Productive Patterns
- Streamer
- Woolly Bugger
- Blue Winged Olive
- Muddler Minnow
Tips
October is the Jefferson's best month for large fish. Pre-spawn brown trout are territorial and strike large streamers. Fish the bends and log-jam pools downstream.
Water Notes
300–600 cfs. Cold and clear. Water 42–54°F. Perfect streamer conditions.
November Outlook
November on the Jefferson transitions to winter. Brown trout spawning wraps up in the braided sections. Midge fishing in the deeper pools on mild days. A quiet month on this underrated river.
Productive Patterns
- Zebra Midge
- RS2
- Pheasant Tail
- WD-40
Tips
The deep bends near Waterloo can fish on mild November afternoons. The Jefferson is quiet in November — you'll likely have the river to yourself. Fish noon–2pm.
Water Notes
400–800 cfs. Cold 38–48°F. Stable fall flows. Valley sections can freeze at night.
December Outlook
December ends the Jefferson season. Cold and quiet with occasional midge activity on the warmest days. The river is best left for the spring season.
Productive Patterns
- Zebra Midge
- RS2
- Midge Larva
Tips
December on the Jefferson is for the very local and dedicated. Target the deepest pools in the braided sections near Twin Bridges on mild days. Plan instead for May.
Water Notes
300–700 cfs. Cold — 32–40°F. Valley sections may freeze. Limited fishing potential.
Hatch Calendar
| Insect | Peak | Active | Size | Productive Patterns |
|---|---|---|---|---|
| Blue Winged Olive Baetis tricaudatus |
Apr, Oct | Mar, Apr, May, Sep, Oct | #18–22 |
|
| Caddis Hydropsyche / Brachycentrus spp. |
Jul, Aug | May, Jun, Jul, Aug, Sep | #14–18 |
|
| Pale Morning Dun Ephemerella inermis |
Jul | Jun, Jul, Aug | #16–18 |
|
| Hoppers Acrididae / Tettigoniidae |
Aug | Jul, Aug, Sep | #8–12 |
|
| Trico Tricorythodes spp. |
Aug | Aug, Sep | #20–24 |
|
Access & Approach
Twin Bridges and Waterloo, MT are the main launch points. Multiple Montana FWP public access sites along the valley. Float boat strongly recommended for the lower river. Manage summer heat — fish early morning and evening in August.
Nearby Fly Shops
- The Stonefly Inn & Fly Shop
- Madison River Fishing Company
- Fins & Feathers of Bozeman
- Sunrise Fly Shop
- Rivers Edge
- Yellow Dog Flyfishing
Regulations & License
Fishing in Montana requires a current license. Always verify season dates, bag limits, and any special-regulation waters before you fish.
Montana fishing regulations & license →
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About Current
Jefferson River conditions on Current combine real-time flow data (USGS, WSC, CDEC, CEHQ), weather, tide predictions, hatch probabilities calibrated to this specific water, and recent fly shop reports from the area.
Jefferson River is one of 245 hand-curated waters in Current. The app and web forecast also generate AI outlooks for any unlisted river, lake, or saltwater flat anywhere in the world — drop a pin or paste a name and Current produces a fresh seasonal outlook with weather, flow context, and recommended techniques.
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