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Legendary Species · Idaho

Cutthroat trout in Idaho

Oncorhynchus clarkii[1]

104 Idaho waters whose agency species list names cutthroat trout. Each links to its water page (gauge, regulations, access map, guides and shops) and to the agency list it comes from.

  • 104waters list it
  • 3destination hubs
A cutthroat trout laid on a white sheet beside a pen for scale, dark-spotted with red-orange colour under the jaw
Cutthroat trout (Oncorhynchus clarkii), photographed by James E. Johnson for the U.S. Fish and Wildlife Service. Photo: James E. Johnson, U.S. Fish and Wildlife Service, public domain, via Wikimedia Commons

Idaho waters

Most fished first. A species missing from an agency list does not mean it is absent; this page lists only waters whose list names it (at least 5 are needed for a page).

All Idaho watersCutthroat trout: every state

Identification

  • Cutthroat trout get their name from the red slashes near the lower jaw.[2]
    What the source says
    “Cutthroat trout are so named for the red slashes near the lower jaws.”
  • Utah DWR says that, except for the Bear Lake form, cutthroat are best told by the crimson slash along the lower jaw, and that they lack the rainbow trout's iridescent pink stripe and white-tipped pelvic and anal fins.[3]
    What the source says
    “Except for the Bear Lake cutthroat trout, cutthroats are best distinguished by their crimson slash along the lower jaw. Cutthroat trout lack the iridescent pink stripe or the white-tipped pelvic and anal fins of the rainbow trout.”

More on identifying cutthroat trout

Status, protections and rules

As each agency stated them on the date read; a rule applies only where its agency says so. Check the current regulations for the water before you fish.

  • Westslope cutthroat: Montana FWP says it has been designated a Fish of Special Concern in Montana.[2]
    What the source says
    “it has been designated a Fish of Special Concern in Montana.”
  • Yellowstone cutthroat: non-native lake trout caused a dramatic decline in Yellowstone cutthroat in the early 2000s.[4]
    What the source says
    “Nonnative lake trout caused a dramatic decline in YCT in the early 2000s.”
  • Colorado River cutthroat: Colorado Parks and Wildlife lists its status as State Special Concern.[5]
    What the source says
    “State Special Concern”
  • Greenback cutthroat: Colorado Parks and Wildlife lists it as federally threatened and state threatened.[6]
    What the source says
    “Federally Threatened, State Threatened”
  • Lahontan cutthroat: listed as threatened under the federal Endangered Species Act (CDFW).[7]
    What the source says
    “Lahontan cutthroat trout are a threatened species under the Federal Endangered Species Act.”

Water temperature in Idaho

  • Under 66°FIn the study Idaho Fish and Game cites, trout landed in water under 66°F survived best: mortality “was 69% higher for trout landed at 73°F water temperatures than for those landed when waters were less than 66°F.” In summer, “early-mornings are typically best while the water is still cool.”
  • WarmingIdaho Fish and Game cites a study in which mortality “was 69% higher for trout landed at 73°F water temperatures than for those landed when waters were less than 66°F.” Fish early: “early-mornings are typically best while the water is still cool.”
  • 73°FIdaho Fish and Game: “On those occasions where trout streams do get above 73°F, anglers may want to pause fishing because catch rates are noticeably lower.” Idaho sets no temperature closure: “Idaho Fish and Game is hesitant to close fishing in wild trout waters based on warm water temperatures.”

Sources: Perspective: Trout fishing during low water and high temperatures (25 July 2024; archived copy) (Idaho Department of Fish and Game); The heat is on, but trout and other coldwater fish have been around the block a time or two (9 Aug 2022; archived copy) (Idaho Department of Fish and Game).

Destination hubs

Hubs that list one of these waters, or that a water page is near: each has guides, shops, licences and trip planning for the area.

Hatch & season charts

Sources

Every fact on this page is our paraphrase of the page cited beside it, read on the date shown. Rules and seasons change: check the agency's current regulations before you fish.

  1. Bonneville Cutthroat Trout (Oncorhynchus clarkii utah) | U.S. Fish & Wildlife Service U.S. Fish and Wildlife Service, read Oct 24, 2026.
  2. Westslope Cutthroat Conservation & Restoration | Montana FWP Montana Fish, Wildlife & Parks, read Oct 24, 2026.
  3. 2026 Utah Fishing Guidebook Utah Division of Wildlife Resources, read Oct 24, 2026.
  4. Fish Ecology - Yellowstone National Park (U.S. National Park Service) National Park Service, read Oct 24, 2026.
  5. Colorado River Cutthroat Trout | Colorado Parks and Wildlife Colorado Parks and Wildlife, read Oct 24, 2026.
  6. Greenback Cutthroat Trout | Colorado Parks and Wildlife Colorado Parks and Wildlife, read Oct 24, 2026.
  7. Lahontan Cutthroat Trout California Department of Fish and Wildlife, read Oct 24, 2026.