The 2026 Fall Mack Days fishing event is officially returning to Flathead Lake from Thursday, September 10 to Sunday, November 8. The Big Ticket: $10,000 Tagged Fish & Massive Cash PrizesThis fall’s prize pool features serious cash incentives:Tagged Lake Trout: Over 9,000 tagged lake trout will be swimming in Flathead Lake worth anywhere from $100 to $500 , alongside major tagged fish valued at $1,000 (5 available) , $5,000 (3 available) , and a grand prize tagged trout worth $10,000 ! Over 9,000 tagged lake trout will be swimming in Flathead Lake worth anywhere from , alongside major tagged fish valued at , , and a grand prize tagged trout worth ! Bonuses kick in starting at 11 lake trout: 11–30 entries: $45 31–50 entries: $88 51–75 entries: $150 76–100 entries: $205 205–225 entries: $518 301–325 entries: $813 (and increasing from there!) All lake trout must be entered on the exact day they are caught.