Fall Mack Days is a lake trout fishing event on Flathead Lake. The Confederated Salish and Kootenai Tribes (CSKT) run it to reduce the lake's non-native lake trout (mackinaw) and protect native bull trout and westslope cutthroat. The 2026 fall event runs from September 10 through November 8, with fish check-ins Friday through Sunday at several lakeside sites and Monday through Thursday at Blue Bay. Anglers registered for the event can fish any day it runs. Every lake trout you turn in counts toward cash drawings, and a few tagged fish are worth up to $10,000.
Two weeks into the 2026 event, anglers had turned in nearly 4,000 lake trout, and the $10,000 tagged fish was still in the lake (Montana Outdoor). This post covers how the event works, why it matters for native fish, and how to fish it on a guided Flathead Lake charter.
[PHOTO: Client holding a Flathead Lake lake trout, with fall color or the Mission Mountains behind. Alt text: "Angler holding a lake trout caught during Fall Mack Days on Flathead Lake, Montana"]
Key Takeaways: Fall Mack Days 2026
- Dates: Thursday, September 10 through Sunday, November 8, 2026 (9 weeks).
- Who runs it: the Confederated Salish and Kootenai Tribes' fisheries program.
- Why: to reduce non-native lake trout in Flathead Lake and help native bull trout and westslope cutthroat.
- Prizes: one $10,000 tagged lake trout, three $5,000 tagged fish, five $1,000 tagged fish, and thousands more tagged fish worth $100–$500, plus weekend lottery drawings.
- Early numbers: 3,983 lake trout turned in after two weeks, 2,156 of them in week two alone.
- Registration: online through mackdays.com. Registration stays open until the event ends.
- Charters count: a guided Flathead Lake fishing charter is an easy way to fish Mack Days if you're visiting without a boat.
What Is Mack Days?
Mack Days is a series of lake trout fishing events on Flathead Lake, held in the spring and fall. "Mack" is short for mackinaw, the local name for lake trout. It is not a typical fishing tournament. The goal is conservation: every lake trout removed from the lake is one fewer predator competing with native fish.
Lake trout are not native to Flathead Lake. According to the event organizers, Mack Days is a tool to reduce their numbers while protecting native bull trout and westslope cutthroat trout. Bull trout are federally listed as threatened, so the fishing you do during Mack Days helps them directly.
2026 Fall Mack Days Schedule and Check-In
Fishing days and check-in rules differ between weekdays and weekends:
| Days | What counts | Where to check in fish |
|---|---|---|
| Monday–Thursday | Tagged fish and bonuses | Blue Bay only, noon to 30 minutes before sunset (after-hours drop box available) |
| Friday–Sunday | Lottery drawings, tagged fish, bonuses, and special categories including top angler | Blue Bay (headquarters), Somers Boat Access, Wayfarers, Big Arm Boat Ramp, and Salish Point, each at set times |
Check-in hours at each site are posted on the official Mack Days events page. Always check current details there before you fish, since the organizers set the rules and can change them.
How Big Are the Prizes?
The biggest draw is the tagged fish. For fall 2026, the organizers have released tagged lake trout worth:
- $10,000 — one fish
- $5,000 — three fish
- $1,000 — five fish
- $100–$500 — more than 9,000 fish
Every lake trout you turn in also counts as an entry in the lottery drawings. The more fish you turn in, the better your odds. Full prize details are posted on mackdays.com.
[PHOTO: Lake trout coming over the gunwale or in the net. Alt text: "Lake trout being netted on a guided Flathead Lake fishing charter"]
How Lake Trout Fishing Works in the Fall
Fall is one of the best times to fish Flathead Lake for lake trout. The summer crowds are gone, the boat traffic drops, and the fish feed actively ahead of winter. On our charters, we target lake trout by jigging, trolling, and vertical presentations, depending on where the fish are holding that day.
Flathead Lake is the largest natural freshwater lake west of the Mississippi, and finding fish is most of the challenge. A guide who fishes the lake regularly will know the depths, structure, and patterns to look for, so your time goes into catching fish rather than searching for them.
Fishing Mack Days on a Guided Charter
If you're visiting Montana without your own boat, a guided charter is the simplest way to fish Mack Days. Our Flathead Lake fishing charter includes:
- A licensed fishing guide and a fully equipped boat
- Rods, reels, tackle, and bait
- A cooler with bottled water (lunch or snacks depending on trip length)
- All safety gear
- Private charters for groups of 4–6 anglers, depending on the boat
It suits all skill levels, and families and kids are welcome. If some of your group would rather sightsee than fish, try the Flathead Lake Charter + Wild Horse Island Tour.
Before your trip, register for Mack Days online at mackdays.com, and ask us how we handle check-in for fish caught on the charter.
License and Permit Requirements for Flathead Lake
You need a valid license or permit to fish Flathead Lake. The southern half of the lake is within the Flathead Indian Reservation, where anglers who are not tribal members need a CSKT tribal fishing permit (CSKT Tribal Fish & Game). The northern half requires a Montana fishing license, which you can buy online through Montana FWP. Tell us where you're launching from and we'll confirm which you need.
Why Mack Days Matters for Native Fish
Lake trout compete with and prey on native fish. Bull trout, which move between Flathead Lake and its tributary rivers to spawn, are especially vulnerable. Montana Fish, Wildlife & Parks is also moving in the same direction: its proposed 2027–28 regulations would remove the possession limit on lake trout in the Western District to reduce pressure on bull trout (Flathead Beacon). The state Fish and Wildlife Commission is scheduled to consider the proposal on October 14, 2026.
Keeping and turning in your lake trout helps native fish in the Flathead system.
FAQs: Fall Mack Days on Flathead Lake
When is Fall Mack Days 2026?
Fall Mack Days 2026 runs from Thursday, September 10 through Sunday, November 8, 2026, a nine-week event on Flathead Lake. Registered anglers can fish any day. Weekday fish (Monday–Thursday) count toward tagged fish and bonuses, and weekend fish (Friday–Sunday) also count toward lottery drawings and top-angler categories.
What is the biggest prize in Mack Days?
For fall 2026, the top prize is a single tagged lake trout worth $10,000. There are also three $5,000 tagged fish, five $1,000 tagged fish, and more than 9,000 tagged fish worth $100 to $500. Every lake trout turned in also counts as an entry in the lottery drawings.
Who organizes Mack Days and why?
Mack Days is run by the Confederated Salish and Kootenai Tribes. It is designed to reduce the number of non-native lake trout in Flathead Lake, which helps protect native bull trout and westslope cutthroat trout. Bull trout are listed as threatened under the federal Endangered Species Act.
Can I fish Mack Days on a guided charter?
Yes. A guided Flathead Lake charter is the easiest way for visitors without a boat to fish Mack Days. Register yourself online at mackdays.com before the trip. The charter provides the boat, guide, rods, tackle, and bait, and the guide takes you to where the lake trout are holding that day.
Do I need a license to fish Flathead Lake?
Yes. The southern half of Flathead Lake lies within the Flathead Indian Reservation, where non-tribal-member anglers need a CSKT tribal fishing permit. The northern half requires a Montana fishing license from Montana Fish, Wildlife & Parks. Your guide can confirm which one you need based on where the trip launches.
Is fall a good time to fish Flathead Lake for lake trout?
Yes. Fall brings fewer boats, cooler weather, and active lake trout feeding ahead of winter. During Mack Days, every lake trout you keep also counts toward cash prizes and helps native fish. Guides typically use jigging, trolling, and vertical presentations, depending on where fish are holding.
Book a Fall Flathead Lake Charter
The $10,000 fish is still out there. Book a Flathead Lake fishing charter, or call 406-607-1165 and we'll help you find a fall date that works. Riverstone Outfitters is a veteran-owned, licensed Montana outfitter (MT Outfitter #63826) based in Bigfork on Flathead Lake.
Event dates, check-in hours, and prizes are set by the Confederated Salish and Kootenai Tribes and can change. Confirm current rules at mackdays.com before you fish. Catch totals are as reported through week two of the 2026 fall event.
