What special fishing regulations apply at Flathead Lake?

Flathead Lake carries 3 special-regulation overlays that override Montana's statewide 2026 rules, covering Kokanee salmon and Lake trout (Mackinaw). One of them reads: "Lake trout (Mackinaw) 100 / day with only 1 over 36 in + all 30-36 in released (FWP/CSKT co-managed Mackinaw suppression — Tribes manage the south half, FWP the north half — spring + fall Mack Days harvest derby pays anglers per fish to protect native bull trout + westslope cutthroat); bull trout angling closed — release immediately (federally Threatened ESA); cutthroat trout CATCH-AND-RELEASE only; lake whitefish 100 / day; yellow perch no limit (only 10 / day over 10 in); a Flathead Reservation Tribal Permit is required for the southern portion of the lake." Every overlay on this water body is listed in full above.

Do I need a fishing license to fish Flathead Lake?

Yes. Flathead Lake is in Montana, so a valid Montana fishing license is required just as it is anywhere else in the state, issued by Montana Fish, Wildlife & Parks (FWP). The special regulations on this page change the bag, size, slot, or gear rules for Flathead Lake; they do not waive the license requirement. Free-fishing days and youth exemptions follow the statewide Montana rules.

Do Flathead Lake's special rules replace Montana's statewide limits?

Only where they conflict. Montana's statewide 2026 regulations apply on Flathead Lake by default; the overlays above replace the matching statewide rules for the species or gear they name, while everything not specifically overridden still follows the statewide rule. When a water-body rule and the statewide rule disagree, the water-body rule wins.

Which species have special rules on Flathead Lake?

Kokanee salmon and Lake trout (Mackinaw) have a water-body-specific rule on Flathead Lake, each linking to its full Montana regulations above. Species not listed here follow the statewide Montana limits.

2026 regulation year

Flathead Lake 2026 — Montana Fishing Regulations

Montana statewide rules apply unless overridden below.

Last updated June 8, 2026

Flathead Lake carries 3 special-regulation overlays on top of Montana's 2026 fishing rules — covering Kokanee salmon, Lake trout (Mackinaw). Verify the agency booklet before launching: in-season changes are not yet wired to this page.

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State-level special regulation

Lake trout (Mackinaw) 100 / day with only 1 over 36 in + all 30-36 in released (FWP/CSKT co-managed Mackinaw suppression — Tribes manage the south half, FWP the north half — spring + fall Mack Days harvest derby pays anglers per fish to protect native bull trout + westslope cutthroat); bull trout angling closed — release immediately (federally Threatened ESA); cutthroat trout CATCH-AND-RELEASE only; lake whitefish 100 / day; yellow perch no limit (only 10 / day over 10 in); a Flathead Reservation Tribal Permit is required for the southern portion of the lake
Source: Montana special-water list

Per-species rules on Flathead Lake

Kokanee salmon regulations →
Western District standard 20 / day (40 in possession); a fraction of its historic McDonald Creek run after the 1980s Mysis shrimp collapse + lake trout explosion
Lake trout (Mackinaw) regulations →
100 / day with only 1 over 36 in + all 30-36 in released (FWP/CSKT co-managed Mackinaw suppression — Tribes manage the south half, FWP the north half); spring + fall CSKT Mack Days harvest derby pays anglers per lake trout

Official source

Montana Fish, Wildlife & Parks (FWP) publishes the authoritative 2026 Montana fishing regulations. Special-regulation lakes and rivers are listed in the agency booklet — always verify before fishing.

Visit official Montana fishing regulations →

Emergency-order channel

In-season closures, slot-limit changes, and run-count-driven harvest pauses are posted to Montana Fish, Wildlife & Parks's emergency-order feed — check it before any Montana trip during the active season.

Other special-regulation waters in Montana

Browse all water bodies →

Frequently asked questions

What special fishing regulations apply at Flathead Lake?: Flathead Lake carries 3 special-regulation overlays that override Montana's statewide 2026 rules, covering Kokanee salmon and Lake trout (Mackinaw). One of them reads: "Lake trout (Mackinaw) 100 / day with only 1 over 36 in + all 30-36 in released (FWP/CSKT co-managed Mackinaw suppression — Tribes manage the south half, FWP the north half — spring + fall Mack Days harvest derby pays anglers per fish to protect native bull trout + westslope cutthroat); bull trout angling closed — release immediately (federally Threatened ESA); cutthroat trout CATCH-AND-RELEASE only; lake whitefish 100 / day; yellow perch no limit (only 10 / day over 10 in); a Flathead Reservation Tribal Permit is required for the southern portion of the lake." Every overlay on this water body is listed in full above.
Do I need a fishing license to fish Flathead Lake?: Yes. Flathead Lake is in Montana, so a valid Montana fishing license is required just as it is anywhere else in the state, issued by Montana Fish, Wildlife & Parks (FWP). The special regulations on this page change the bag, size, slot, or gear rules for Flathead Lake; they do not waive the license requirement. Free-fishing days and youth exemptions follow the statewide Montana rules.
Do Flathead Lake's special rules replace Montana's statewide limits?: Only where they conflict. Montana's statewide 2026 regulations apply on Flathead Lake by default; the overlays above replace the matching statewide rules for the species or gear they name, while everything not specifically overridden still follows the statewide rule. When a water-body rule and the statewide rule disagree, the water-body rule wins.
Which species have special rules on Flathead Lake?: Kokanee salmon and Lake trout (Mackinaw) have a water-body-specific rule on Flathead Lake, each linking to its full Montana regulations above. Species not listed here follow the statewide Montana limits.

← Back to Montana regulations overview