lamar-river

Lamar River is a river in Wyoming.

It ranks #6 among the 11 waters of Wyoming in the registry, and is of national prominence.

Also called The Lamar.

Fished for trout (inferred from the species listed).

Species: cutthroat trout and rainbow trout.

USGS GNIS record: 1600818.

Stretches: Lamar Valley, Lamar Valley to Yellowstone River Confluence and Headwaters to Soda Butte Creek.

Confluences: Yellowstone River confluence.

Slough Creek confluence (confluence). It is fishable. Slough Creek is a major tributary to the Lamar (Firehole Ranch). Shared with the Slough Creek record.

Soda Butte Creek confluence (confluence). It is fishable. Montana Angler: the Lamar reaches the road at its confluence with Soda Butte Creek. Shared with the Soda Butte Creek record.

Sourced from 1 independent fly site.

Sources: fireholeranch.com (retrieved 2026-10-20), fireholeranch.com (2) (retrieved 2026-10-20) and Montana Angler (retrieved 2026-10-20).

Hatches

Gray Drake

Sourced.

  1. Jan
  2. Feb
  3. Mar
  4. Apr
  5. May
  6. Jun hatching, peak
  7. Jul hatching, peak
  8. Aug
  9. Sep
  10. Oct
  11. Nov
  12. Dec

Peak: June 20 - July 20

Sources: fireholeranch.com

Terrestrials (hoppers, ants, beetles)

Sourced.

  1. Jan
  2. Feb
  3. Mar
  4. Apr
  5. May
  6. Jun
  7. Jul hatching, peak
  8. Aug hatching
  9. Sep hatching, peak
  10. Oct
  11. Nov
  12. Dec

Peak: July 1 - September 30

The main draw once the river clears.

Sources: fireholeranch.com, Montana Angler

Heptagenia mayflies (Heptagenia)

Sourced.

  1. Jan
  2. Feb
  3. Mar
  4. Apr
  5. May
  6. Jun
  7. Jul
  8. Aug hatching, peak
  9. Sep hatching, peak
  10. Oct
  11. Nov
  12. Dec

Peak: August 1 - September 15

Sources: fireholeranch.com

Hydropsyche Caddis (Hydropsyche)

Sourced.

  1. Jan
  2. Feb
  3. Mar
  4. Apr
  5. May
  6. Jun hatching, peak
  7. Jul hatching, peak
  8. Aug
  9. Sep
  10. Oct
  11. Nov
  12. Dec

Peak: June 15 - July 31

Sources: fireholeranch.com

Drake Mackerel (late-season drake)

Sourced.

  1. Jan
  2. Feb
  3. Mar
  4. Apr
  5. May
  6. Jun
  7. Jul
  8. Aug
  9. Sep hatching, peak
  10. Oct
  11. Nov
  12. Dec

Peak: September 1 - September 20

Sources: fireholeranch.com

Salmonfly

Sourced. Sources give different windows; this shows the range.

  1. Jan
  2. Feb
  3. Mar
  4. Apr
  5. May
  6. Jun hatching, peak
  7. Jul hatching, peak
  8. Aug
  9. Sep
  10. Oct
  11. Nov
  12. Dec

Peak: June 25 - July 10

Reported timing differs: one source gives June 25-July 10; another ties the hatch to the water clearing, with runoff subsiding mid-July. Canyon above the Northeast Entrance bridge.

Sources: fireholeranch.com, Montana Angler

Blue-Winged Olive (Baetis)

Sourced.

  1. Jan
  2. Feb
  3. Mar
  4. Apr
  5. May
  6. Jun
  7. Jul
  8. Aug hatching, peak
  9. Sep hatching, peak
  10. Oct
  11. Nov
  12. Dec

Peak: August 20 - September 30

Sources: fireholeranch.com

Green Drake

Sourced.

  1. Jan
  2. Feb
  3. Mar
  4. Apr
  5. May
  6. Jun
  7. Jul hatching, peak
  8. Aug
  9. Sep
  10. Oct
  11. Nov
  12. Dec

Peak: July 1 - July 20

Drakes (green, gray or tan) bring fish up; the Lamar clears late.

Sources: fireholeranch.com, Montana Angler

Golden Stonefly

Sourced.

  1. Jan
  2. Feb
  3. Mar
  4. Apr
  5. May
  6. Jun
  7. Jul hatching, peak
  8. Aug
  9. Sep
  10. Oct
  11. Nov
  12. Dec

Peak: as water clears (mid-July or later)

Canyon above the Northeast Entrance bridge.

Sources: Montana Angler

Also named, timing not yet researched: Pale Morning Dun.

Access, closures and rules change; check with the state agency before you go.