Troutline

North Platte River

Wyoming·North Platte Basin·42.55° N, 106.75° W
Flow
1,070 CFS
N Platte R above Seminoe Reservoir near Sinclair
Water Temp
—
Condition
Well Below Normal
Weather
35°F
Rain And Snow Showers

Insights

Lunar
New moon tonight
Dark nights — fish are more likely to feed through the day.
Flow
Low flows at 1,070 CFS
Fish are spooky. Lighten tippet and lengthen leaders.
Pressure
Pressure rising
Feeding may slow as fish sit tight.
Wind
Wind 18 mph — strong
Shorter casts and heavier flies. Find a bank with cover.
Sky
Rain incoming
Surface activity often spikes ahead of the soaking — watch the window.

Central Wyoming's North Platte is a string of dam-controlled tailwaters that produces some of the highest trout densities in the West. The named fly fishing water is concentrated in three sections — Miracle Mile, Fremont Canyon, and Grey Reef — together totaling about 100 miles of cold, fertile, year-round river. Grey Reef in particular is rated Blue Ribbon by Wyoming Game & Fish and supports more than 8,000 trout per mile in its upper twelve miles, averaging 16-19 inches.

It fishes as a tailwater first. Flow is regulated by Kortes, Pathfinder, and Alcova / Gray Reef dams; releases are tuned by the Bureau of Reclamation for irrigation rather than fishing, so seasonal flow patterns matter a lot. Sow bugs, scuds, and small midges drive the bug calendar — these aren't classic salmonfly-and-PMD freestoners. Mid-summer Trico spinner falls and fall BWO hatches open dry-fly windows, but the daily bread-and-butter is deep nymphing heavy attractor rigs through long runs. Streamer fishing is excellent fall through spring, especially for the resident brown trout in the deeper holding water below Grey Reef and through Miracle Mile.

The corridor town is Casper, an hour east of Grey Reef and 90 minutes from Miracle Mile and Fremont Canyon. Driving distances put the river outside most weekend trip ranges, which keeps pressure manageable even on the famous water — locals and destination anglers split the traffic. The 2026 regulation refresh tightened gear restrictions: single-point barbless hooks are now required on Miracle Mile, Alcova Afterbay, Fremont Canyon, and Grey Reef; pegged attractors are banned at Fremont Canyon and Grey Reef; the artificial-flies-and-lures section at Grey Reef extends downstream to Government Bridge; and a new spawning closure from Ledge Creek downstream is in effect April 1 – May 15 each year. Note that current Grey Reef flow data comes from NWPS observation only — the USGS Alcova gauge no longer reports live data.

Species

SpeciesAbundanceBest SeasonSizeNotes
Rainbow TroutAbundantYear-round14-22"Wild-reproducing in Grey Reef (the upper 12 miles holds 8,000+ fish per mile), supplemented by stocking elsewhere. Average Grey Reef rainbow runs 16-19 inches; trophy fish over 24 inches show every season.
Brown TroutCommonSep-Nov14-26"Concentrated in Miracle Mile and the deeper holding water below Grey Reef. Best targeted on streamers in fall pre-spawn aggression.
Cutthroat TroutRareYear-round12-16"Scattered presence; not a primary target.
Mountain WhitefishCommonYear-round10-16"Native and present throughout the system. Take small nymphs aggressively and often save slow days.
Ideal wading flow400–1,500 CFS
Blow-out>4,000 CFS
Ideal water temp40–58°F

October-November (brown pre-spawn, BWO, streamers), March-April (rainbow spawn, midges, BWO), July-August (Trico spinner falls, dry-fly windows). The tailwaters fish 12 months — water temperature is stable year-round.

Sections

5 sections on this river

Grey Reef to Casper

FloatBrown Trout · Rainbow Trout

Roughly 55 miles of float water from below Government Bridge through Bessemer Bend and into Casper. Bigger water than the upper tailwater, productive for brown trout in the deep holding runs and rainbow trout through the riffles. Less crowded than the Reef itself.

Best for: Brown trout and rainbow trout on streamers, attractor nymphs, and hopper-droppers in summer. Multi-day float water for experienced rowers.

Grey Reef Tailwater (Gray Reef Dam to Government Bridge)

Wade & FloatBrown Trout · Rainbow Trout

The signature WY North Platte fly fishing section. Twelve miles below the Gray Reef Dam holds 8,000+ wild rainbow trout per mile, averaging 16-19 inches. Float fishing from the Lusby Public Access put-in is the standard guide trip. Artificial flies and lures only, single-point barbless, no pegged attractors as of 2026. Spawning closure below Ledge Creek April 1 – May 15.

Best for: Trophy wild rainbow trout on sow bugs, scuds, eggs, midges, and BWOs. Brown trout on streamers in fall and spring. The Blue Ribbon guide-float section.

Fremont Canyon (Pathfinder Dam to Alcova Reservoir)

WadeBrown Trout · Rainbow Trout

Three miles of meadow water below Pathfinder Dam followed by a rugged canyon of vertical walls and pocket water. Typical flows are very low — under 100 CFS — making this a wade fishery only. Pegged attractors banned as of 2026.

Best for: Rainbow trout and brown trout on small nymphs, midges, and tight technical dry-fly. Drive-in access at the Pathfinder Dam parking area or the bottom of the canyon. Walk-and-wade only.

Miracle Mile (Kortes Dam to Pathfinder Reservoir)

Wade & FloatBrown Trout · Rainbow Trout

Five to eight miles of tailwater (length fluctuates with Pathfinder reservoir level) below Kortes Powerplant. Steep canyon walls, large boulders, pocket water, classic riffle-and-run scenarios. WY G&F electrofishing shows ~3,200 trout per mile. Single-point barbless hooks required as of 2026.

Best for: Rainbow trout and brown trout on stonefly nymphs, sow bugs, scuds, and streamers in fall. Wade or row a small raft.

Saratoga / Pick Bridge (Upper River)

Wade & FloatBrown Trout · Rainbow Trout

The upper free-flowing North Platte between Saratoga and Sinclair (above Seminoe Reservoir). Freestone-style water with stonefly hatches, less famous than the tailwaters downstream. Some private access; public reach near Saratoga and around Pick Bridge.

Best for: Wild brown trout and rainbow trout on stonefly nymphs, streamers, and attractor dries. Best Jul-Oct.

Regulations

Current fishing rules and restrictions

2026 regulations tightened gear restrictions in the Miracle Mile, Fremont Canyon, and Grey Reef tailwaters. Single-point barbless hooks required throughout these sections; pegged attractors banned at Fremont Canyon and Grey Reef; artificial flies and lures only at Grey Reef from the dam downstream to Government Bridge; spawning closure below Ledge Creek April 1 – May 15.

  • Miracle Mile (Kortes Dam to Pathfinder Reservoir): single-point barbless hooks required; year-round
  • Fremont Canyon (Pathfinder Dam to Alcova Reservoir): single-point barbless required; pegged attractors prohibited
  • Grey Reef (Gray Reef Dam to Government Bridge): artificial flies and lures only; single-point barbless; pegged attractors prohibited; spawning closure below Ledge Creek April 1 – May 15
  • Standard WY trout limits apply elsewhere on the river (6 trout daily)
  • WY resident or non-resident fishing license required throughout
  • Commercial guides must register their boats annually with WY G&F (mandatory as of 2026)

The Bureau of Reclamation manages flow releases on this system for irrigation. Spring 'flush' flows above 4,000 CFS can briefly make Grey Reef unfishable. Check the NWPS Gray Reef gauge before driving in.

Source: Wyoming Game and Fish Department — Fishing Regulations. Regulations change annually — verify before fishing.

Access & Logistics

Getting there, fly shops, and lodging

Getting There

Casper, WY

30 min from Casper to Grey Reef, 90 min from Casper to Miracle Mile; 3 hrs from Cheyenne; 4 hrs from Denver; 8 hrs from Salt Lake City

Lodges

Camping & Lodging

Public camping at Pathfinder Reservoir (Pathfinder NWR), Alcova Reservoir, and the Miracle Mile (BLM dispersed camping). Streamside lodges at North Platte Lodge (Alcova) and Grey Reef Wingshooting & Fly Fishing Lodge. Hotels and short-term rentals in Casper.

Grey Reef public access starts at the Lusby Public Access put-in below the dam. Miracle Mile has dirt-road BLM access from Kortes Powerplant downstream. Fremont Canyon access is foot-only from the Pathfinder Dam parking area or the bottom of the canyon. Float trips are the standard Grey Reef guide trip; Miracle Mile and Fremont Canyon are wade-only.

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

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Other regions

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