The 2026 Spring Mack Days Fishing Event on Flathead Lake highlights angler participation in lake trout conservation, with daily catches peaking at 1,680 and notable tagged fish prizes. Event runs until May 9th.

Mack Days returns to Flathead Lake March 12–May 9, 2026, giving anglers nine weeks to target non-native lake trout while supporting conservation of native bull trout and westslope cutthroat. Get the key dates, prize details, entry rules, fish drop-off locations, and important release and fish ID requirements.