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694-acre lake near Charlevoix County. The lake tops out around 152 ft. The depth chart is built from real state fisheries GPS surveys, so the humps, channels and drop-offs you see are measured, not guessed. Species by species, here's what the data says the year looks like.
Traced from the shoreline, Lake Thumb runs 582 acres with 5.3 miles of edge. The shoreline is moderately structured (index 1.6) — enough points and pockets to pattern. About 46% of the surface sits shallower than 15 ft — that's the weed-and-bait zone. Call it 1.9 mi long by 1 mi wide at the broadest reach. The water lies in Charlevoix County. The nearest mapped water is Hoffman Lake, 4 mi to the south.
Spring puts lake trout in skinny water — 10 to 40 ft is the zone. As the season builds they drop to 50 to 120 ft, wintering in 20 to 80 ft. Spring lake trout concentrate at Main-lake point, a prime-rated point around 7 ft. Warm-month bites cluster around early morning. A white tube jig (deep) or a magnum spoon on downrigger covers the summer program.
| Season | Depth | Best window | Start at | Go-to baits |
|---|---|---|---|---|
| Spring | 10 to 40 ft | dawn & dusk | Main-lake point (7 ft) | Casting spoon over shoals, Jerkbait (shallow) |
| Summer | 50 to 120 ft | dawn | Deep basin (151 ft) | White tube jig (deep), Magnum spoon on downrigger |
| Fall | 10 to 50 ft | dusk & dawn | Main-lake point (7 ft) | Heavy casting spoon, Jigging rap over reefs |
| Winter | 20 to 80 ft | dawn | Break off the point (6 ft) | White tube jig, Airplane jig |
In spring, splake run shallow here, mostly 5 to 25 ft. Summer pushes them deeper, 25 to 60 ft, and winter fish settle into 10 to 45 ft. Main-lake point is the standout, a point at roughly 7 ft, rated prime for spring splake. Time it for early morning and the evening. You won't need more than a trolled spoon at the thermocline or a white tube jig (deep) most summer days.
| Season | Depth | Best window | Start at | Go-to baits |
|---|---|---|---|---|
| Spring | 5 to 25 ft | dawn & dusk | Main-lake point (7 ft) | Small casting spoon (gold/orange), Inline spinner |
| Summer | 25 to 60 ft | dawn & dusk | Break off the point (6 ft) | Trolled spoon at the thermocline, White tube jig (deep) |
| Fall | 10 to 35 ft | dawn & dusk | Main-lake point (7 ft) | Casting spoon, Jerkbait |
| Winter | 10 to 45 ft | dawn | Break off the point (6 ft) | Jigging spoon tipped with minnow head, Small white tube |
Spring puts rainbow trout in skinny water — 5 to 20 ft is the zone. Warm water sends them out to 8 to 30 ft; cold water stacks them in 8 to 40 ft. Break off the point is the standout, a drop-off at roughly 6 ft, rated prime for winter rainbow trout. Plan around early morning and the evening in the warm months. A dodger + spoon (deep troll) or a flutter spoon covers the summer program.
| Season | Depth | Best window | Start at | Go-to baits |
|---|---|---|---|---|
| Spring | 5 to 20 ft | dawn & dusk | Main-lake point (7 ft) | Inline spinner (silver), Small spoon |
| Summer | 8 to 30 ft | dawn & dusk | Break off the point (6 ft) | Dodger + spoon (deep troll), Flutter spoon |
| Fall | 10 to 35 ft | dawn & dusk | Main-lake point (7 ft) | Casting spoon, Jerkbait over shoals |
| Winter | 8 to 40 ft | dawn | Break off the point (6 ft) | Jigging spoon, Tube jig (white) |
Come spring, look for brown trout tight to the bank in 3 to 25 ft. They move out to 25 to 60 ft in summer and finish the year down in 5 to 35 ft. If you only fish one area, make it Break off the point: a drop-off around 6 ft that scores prime in winter. Best bite is after dark and early morning. A spoon at the thermocline or a deep stickbait (night) is the honest summer answer here.
| Season | Depth | Best window | Start at | Go-to baits |
|---|---|---|---|---|
| Spring | 3 to 25 ft | dawn & dusk | Main-lake point (7 ft) | Stickbait off planer boards (shallow), Small spoon along mud lines |
| Summer | 25 to 60 ft | night & dawn | Break off the point (6 ft) | Spoon at the thermocline, Deep stickbait (night) |
| Fall | 5 to 30 ft | dusk & dawn | Main-lake point (7 ft) | Jerkbait over gravel, Casting spoon |
| Winter | 5 to 35 ft | dawn | Break off the point (6 ft) | Jigging spoon, Small stickbait (slow) |
Come spring, look for yellow perch tight to the bank in 3 to 12 ft. Expect a summer slide to 10 to 30 ft, then a winter hold in 15 to 35 ft. Start at Shallow bay flat. It's a weed flat holding about 7 ft of water and rates prime come spring. Prime time lands in early morning. A drop-shot micro plastics or a small spoon tipped with worm is the honest summer answer here.
| Season | Depth | Best window | Start at | Go-to baits |
|---|---|---|---|---|
| Spring | 3 to 12 ft | midday & dawn | Shallow bay flat (7 ft) | Small jig + curly tail, Perch-pattern micro crank |
| Summer | 10 to 30 ft | dawn | Break off the point (6 ft) | Drop-shot micro plastics, Small spoon tipped with worm |
| Fall | 12 to 35 ft | midday | Break off the point (6 ft) | Jigging spoon (small), Perch rig / spreader |
| Winter | 15 to 35 ft | midday & dawn | Deep basin (151 ft) | Tungsten jig + spikes, Rattle spoon (small) |
Start shallow in spring: smallmouth bass sit in 3 to 12 ft that time of year. Summer pushes them deeper, 10 to 30 ft, and winter fish settle into 20 to 45 ft. The spot to know is Main-lake point, a point in about 7 ft of water that rates prime for smallmouth bass in fall. Warm-month bites cluster around early morning and the evening. Throw a drop shot (goby/minnow) or a ned rig until the fish tell you otherwise.
| Season | Depth | Best window | Start at | Go-to baits |
|---|---|---|---|---|
| Spring | 3 to 12 ft | dawn & dusk | Main-lake point (7 ft) | Ned rig, Tube jig |
| Summer | 10 to 30 ft | dawn & dusk | Break off the point (6 ft) | Drop shot (goby/minnow), Ned rig |
| Fall | 8 to 25 ft | midday & dawn | Main-lake point (7 ft) | Jerkbait, Blade bait |
| Winter | 20 to 45 ft | midday | Break off the point (6 ft) | Blade bait, Hair jig |
Lake Thumb also holds largemouth bass (8 to 20 ft in summer), crappie (10 to 25 ft in summer), bluegill (4 to 15 ft in summer). Pick any of them on the map above for rated spots and bait picks.
Lake Thumb carries 6 mapped structure features, topping out (or rather bottoming out) at Deep basin, about 151 ft down.
Access data: Michigan DNR — Michigan Boating Access Sites. Confirm conditions and fees locally before you launch.
| Date | Species | Count | Size |
|---|---|---|---|
| Apr 24 | Splake | 10,199 | ~20.1" |
Source: Michigan DNR fish-stocking database, retrieved 2026-08-18.
Season dates, license requirements, and size and bag limits for Michigan waters are set by the Michigan DNR — and special regulations can apply to Lake Thumb specifically, so confirm the current rules before you fish.
Check the official Michigan fishing regulations →
Lake Thumb is about 152 ft (46 m) deep at its deepest point. The depth chart here comes from real state fisheries GPS surveys, so the contours reflect measured depths.
Anglers target lake trout, splake, rainbow trout, brown trout, yellow perch, smallmouth bass, largemouth bass, crappie, bluegill on Lake Thumb. This isn't a survey of the water — none is published for it — but an informed estimate from the species common to the region, narrowed by this water's depth, size and each species' range.
Shallow bay flat is the top-rated area: a weed flat in about 7 ft of water that rates prime for yellow perch in spring. Every other rated spot, per species and season, is on the map above.
For lake trout, the summer bite is best in early morning. Each species page section below lists the seasonal windows, and the map shows a live NOW badge when you're inside one.
Yes — per Michigan DNR fish-stocking database records, Lake Thumb was most recently stocked Apr 24 with 10,199 splake. The full stocking history is listed above.
Fishing on Lake Thumb is regulated by the Michigan DNR. Check the official Michigan regulations for current license requirements, season dates, and size and bag limits — special regulations can apply to this specific water.
Hoffman Lake 4 mi · Weber Lake 8 mi · Silver Lake 8 mi · Lake Twentyseven 10 mi · Lance Lake 10 mi · Five Lakes 10 mi · Deer Lake 10 mi · Pickerel Lake 12 mi · Mud Lake 12 mi · Hackett Lake 13 mi · Walloon Lake 14 mi · Mud Lake 14 mi
See how Lake Thumb stacks up: best largemouth bass lakes in Michigan · best smallmouth bass lakes in Michigan · best crappie lakes in Michigan · best bluegill lakes in Michigan
More water nearby: Charlevoix County fishing maps (16 charts). Browse all Michigan fishing maps or see every water on DepthScout. Bathymetry credit: state fisheries survey programs. How we build these maps. Fish here with a sonar unit that logs? Send us your depth data and we'll improve this chart, credited to you. For fishing guidance only, never navigation.