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Lamar River

Wyoming·Yellowstone National Park·44.89° N, 110.24° W
Flow
764 CFS
Lamar River nr Tower Ranger Station YNP
Water Temp
61°F
Lamar River nr Tower Ranger Station YNP
Condition
Below Normal
Weather
63°F
Mostly Sunny
near Silver Gate
Latest report: Parks' Fly Shop · today

Insights

Water Temp
Water 61°F — prime
Active-feeding window.
Wind
Wind 0 mph — calm
Easy casting and clean surface presentations.
Flow
Blown out at 764 CFS
High, off-color water — tough conditions. Wait for the drop or look elsewhere.

The Lamar is the marquee Yellowstone cutthroat river — a freestone that rolls northwest about 40 miles out of the Absaroka wilderness and through the wide-open Lamar Valley before dumping into the Yellowstone River near Tower Junction. What sets it apart is the combination: genetically pure Yellowstone cutthroat sipping big mayflies against a backdrop of bison and wolves, in water you can sight-fish on foot. The five-to-six-mile meadow stretch from the Soda Butte Creek confluence down to the head of the canyon is the draw — slow glassy runs, undercut banks, and cutthroat that average 14-18 inches with honest shots at fish over 20. This is dry-fly, spot-and-stalk water, not a place to drag a nymph rig blind.

Timing is the whole game, and the Lamar is honest about being difficult early. It's a snowmelt freestone with an enormous, roadless upper drainage, so it runs high and off-color through June — flows were still 886 CFS with 64°F water and a muddy note in early July 2026. It typically clears and comes into shape by mid-July and fishes best from late July through September into October. The catch: the upper backcountry is so large and unstable that any real rain up top can blow the whole river out overnight and dirty it for a day or two, even in August. You learn to check the Tower gauge and keep a Plan B — Soda Butte Creek, Slough Creek, or the Yellowstone — in your pocket.

Access is easy where it matters and brutal where it doesn't. The valley parallels the Northeast Entrance Road, so you park at a pullout and walk to the water; the tradeoff is crowds and wind, since the exposed Lamar Valley gets afternoon gusts that flatten the dry-fly game. This is a wilderness river inside a national park, so you fish under Park rules, not a state license — artificial, barbless, lead-free, and every rainbow or cutbow hybrid you catch in the drainage must be killed to protect the native strain. The canyon below the meadows is smaller, faster pocket water with smaller fish (and the area saw road and access disruption after the 2022 flood), and the true upper river beyond the road is a multi-mile hike into serious grizzly-country backcountry.

Fishing Reports

Latest reports from local fly shops

Species

  • Yellowstone Cutthroat Trout
    Primary · Jul-Oct · 8-20"+

    The signature fish and a genetically pure native strain. Valley meadow fish average 14-18" with real shots at 20"+; backcountry fish run smaller (6-14") but eager. Sight-fishable in the glassy runs. Catch-and-release only — this is native trout conservation water.

  • Rainbow Trout
    Secondary · Jul-Oct · 10-18"

    Invasive; more common in the lower half and the canyon near the Yellowstone confluence. Park regulations require that all rainbows AND cutthroat-rainbow hybrids (cutbows) caught in the Lamar drainage be killed — an invasive-control measure protecting the pure Yellowstone cutthroat strain. Know how to tell a cutbow from a pure cutthroat before you fish here.

Ideal wading flow150450 CFS
Blow-out>600 CFS
Ideal water temp5062°F

Late July-August is the peak — clear water, green and gray drakes, PMDs, and the start of hopper season. September-October brings terrestrials, then fall BWOs, cooler water, and fewer crowds. Mid-July is the opener as the river first clears but it's streaky. Spring through June is unfishable due to runoff. More than a number, watch for muddying: backcountry rain can spike and dirty the Lamar for 1-2 days at any point in summer.

Sections

3 sections on this river

Lamar Canyon (head of canyon to Yellowstone confluence)

WadeSalmon · Cutthroat · Rainbow Trout

Roughly two miles of steeper-gradient canyon — fast pocket water, boulders, and pockets rather than meadow flats, ending at the Yellowstone River confluence near Tower (the USGS gauge sits here). More remote and rugged foot access; the canyon area saw road and access disruption after the 2022 flood.

Best for: Pocket-water Yellowstone cutthroat trout and lower-river rainbow trout on attractor dries and small streamers. The one reach with a salmonfly and golden stone presence, plus the confluence pool water where bigger rainbows hold.

Lamar Valley (Soda Butte confluence to head of canyon)

WadeCutthroat · Rainbow Trout

The famous water — a wide, meandering meadow river with glassy runs, gentle riffles, boulders, and deep undercut banks. Classic spring-creek-style sight-fishing for Yellowstone cutthroat trout despite being a freestone. Roadside access off the Northeast Entrance Road; park at pullouts near the Soda Butte confluence and the Lamar River Trailhead and walk a few hundred yards to a mile.

Best for: Yellowstone cutthroat trout on dry flies — green and gray drakes, PMDs, and hoppers. Prime dead-drift dry-fly and hopper-dropper water, and the postcard meadow experience with bison and wolves around.

Upper Lamar / Backcountry (Lamar River Trail above Soda Butte)

WadeCutthroat · Rainbow Trout

True wilderness freestone — 30-plus miles of roadless drainage into the Absaroka toward Cache Creek and beyond. Smaller, faster water with abundant but modest Yellowstone cutthroat trout. Hike-in only via the Lamar River Trail; multi-mile backcountry travel in grizzly country. This is also the drainage that destabilizes the whole river when it rains — the source of the Lamar's flash blow-outs.

Best for: Numbers of eager Yellowstone cutthroat trout (6-14") on attractor dries, and solitude away from the roadside crowds.

Regulations

Current fishing rules and restrictions

A Yellowstone National Park fishing permit is required — WY and MT state licenses are NOT valid inside the Park. Fly/artificial only, barbless, lead-free. Yellowstone cutthroat are catch-and-release, but the Lamar drainage has a MANDATORY KILL of all rainbow trout, brook trout, and cutthroat-rainbow hybrids to protect the native strain.

  • Yellowstone NP fishing permit required — 3-day ($40), 7-day ($55), or season ($75) options; WY/MT state licenses are NOT valid in the Park (2026 pricing, verify annually)
  • Artificial lures and flies only — no bait
  • Lead-free terminal tackle required (no lead weights, split shot, or jig heads)
  • Barbless hooks required (or barbs pinched down)
  • Yellowstone cutthroat trout: catch-and-release only (native trout conservation water)
  • MANDATORY KILL in the Lamar drainage: all rainbow trout, brook trout, and identifiable cutthroat-rainbow hybrids (cutbows) must be killed
  • Park fishing season: opens the Saturday of Memorial Day weekend, closes the first Sunday in November

The Lamar itself isn't fishable until runoff drops, usually around mid-July. Late-summer afternoons can push water temps into the mid-60s°F — fish early and avoid stressing fish in low, warm flows. The canyon area near Tower saw road and access disruption after the 2022 flood; check current NPS road status before planning a trip to the lower river.

Source: National Park Service — Yellowstone Fishing. Regulations change annually — verify before fishing.

Access & Logistics

Getting there, fly shops, and lodging

Getting There

Cooke City / Silver Gate, MT (NE Entrance) and Gardiner, MT (N Entrance)

45 min from Gardiner, MT to Tower/Lamar; right at the top of the drainage from Cooke City/Silver Gate; ~2.5-3 hrs from Bozeman (BZN) via Gardiner

Fly Shops

Camping & Lodging

In-park: Roosevelt Lodge at Tower Junction plus the Slough Creek and Pebble Creek campgrounds are closest to the Lamar Valley. Town bases are Cooke City and Silver Gate, MT at the Northeast Entrance (top of the drainage) and Gardiner, MT at the North Entrance.

The Northeast Entrance Road parallels the Lamar Valley — park at pullouts and walk a few hundred yards to a mile to productive water. The Lamar River Trail accesses the upper backcountry (grizzly country; overnight trips need a backcountry permit). Park entrance fee plus a Yellowstone fishing permit are required.

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 Wyoming

View all 15 rivers

Other regions

Buffalo Fork RiverWY

The wild, back-of-beyond cousin to the Snake it feeds — a small snowmelt freestone that gathers its North and South Forks deep in the Teton Wilderness and comes together in Buffalo Valley before joining the Snake near Moran. Almost pure Snake River fine-spotted cutthroat water, with mountain whitefish thick enough to rise during a stonefly emergence. The lower river along Buffalo Valley Road is an easy float-or-wade cutthroat float; the upper forks are a backcountry pack trip. No dam to steady it, so it fishes best on the drop from August into September.

Greys RiverWY

A 50-plus-mile freestone that drops out of the Wyoming Range to meet the Snake at Alpine, the Greys is one of the few genuinely wild cutthroat rivers in the West you can fish from a gravel road. More than 95% of its trout are native Snake River fine-spotted cutthroat, and they come up hard for attractor dries from July through October once spring runoff drops out.

Gros Ventre RiverWY

The walk-and-wade counterpart to the crowded Snake River float scene in Jackson Hole — a medium freestone that drops out of the Gros Ventre Wilderness past the 1925 slide and its two slide lakes, then runs through the National Elk Refuge and Grand Teton National Park corridor to meet the Snake. Wild Snake River fine-spotted cutthroat eat attractor dries from July into fall once runoff drops; irrigation diversion pulls the lower river down hard by late summer.

Hoback RiverWY

The small roadside freestone you drive right past heading south out of Jackson — US-189/191 traces it the whole way down Hoback Canyon to the Snake at Hoback Junction. Wade-only water, mostly 15 feet wide, holding native Snake River fine-spotted cutthroat that charge attractor dries. Most fish run 8–13 inches, with bigger migratory Snake River cutthroat pushing up in late spring and early fall; the early-summer salmonfly and golden stone hatches are the marquee event once runoff drops in late June.

New Fork RiverWY

The Upper Green's quieter twin — a willow-lined meadow river dropping out of the New Fork Lakes below the Wind River Range and winding past Pinedale toward the Green near Big Piney. Wild brown trout are the draw (16-20 inches with a real shot at a 5-pounder on fall streamers), with rainbows, brookies up high, and native whitefish throughout. Mostly private ranchland, so it fishes as a float river — but low ranch bridges mean jon boats, not drift boats.

North Platte RiverWY

Central Wyoming's string of dam-controlled tailwaters — Miracle Mile, Fremont Canyon, and the Blue Ribbon Grey Reef — supports more than 8,000 wild rainbow trout per mile in the upper Grey Reef reach. Year-round sow bug, scud, midge, and BWO fishing with brown trout streamer windows in fall and spring.