Lake depth chart
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135-acre lake near St. Joseph County. The lake tops out around 25 ft. The depth chart comes from published agency bathymetric survey data, so the contours are survey-derived rather than computer-modeled. The season-by-season read for each species follows, from the map's own numbers.
On the chart, Thompson Lake draws 149 acres inside 2.1 miles of shoreline. At index 1.2 the outline is almost a bowl — read the depth changes, not the shoreline. Roughly 46% of the water is 15 ft or less, the band where the food chain lives. Figure 0.7 mi of water from one end to the other, 0.5 mi at the beam. The water lies in St. Joseph County. The nearest mapped water is Tamarack Lake, 2 mi to the southwest.
Come spring, look for yellow perch tight to the bank in 3 to 12 ft. Expect a summer slide to 8 to 25 ft, then a winter hold in 8 to 25 ft. Start at Deep basin. It's a deep basin holding about 25 ft of water and rates prime come fall. 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 (2 ft) | Small jig + curly tail, Perch-pattern micro crank |
| Summer | 8 to 25 ft | dawn | Deep basin (25 ft) | Drop-shot micro plastics, Small spoon tipped with worm |
| Fall | 8 to 25 ft | midday | Deep basin (25 ft) | Jigging spoon (small), Perch rig / spreader |
| Winter | 8 to 25 ft | midday & dawn | Deep basin (25 ft) | Tungsten jig + spikes, Rattle spoon (small) |
Start shallow in spring: northern pike sit in 2 to 8 ft that time of year. Summer pushes them deeper, 8 to 20 ft, and winter fish settle into 5 to 15 ft. The spot to know is Shallow bay flat, a weed flat in about 2 ft of water that rates prime for northern pike in spring. Warm-month bites cluster around early morning and the evening. Throw a bucktail or a weedless spoon over cabbage until the fish tell you otherwise.
| Season | Depth | Best window | Start at | Go-to baits |
|---|---|---|---|---|
| Spring | 2 to 8 ft | midday & dawn | Shallow bay flat (2 ft) | #5 inline spinner, Spoon (red/white) |
| Summer | 8 to 20 ft | dawn & dusk | Main-lake point (14 ft) | Bucktail, Weedless spoon over cabbage |
| Fall | 6 to 18 ft | midday & dawn | Main-lake point (14 ft) | Big rubber (Bull Dawg style), Husky-style jerkbait |
| Winter | 5 to 15 ft | midday | Main-lake point (14 ft) | Tip-ups, Large jigging spoon |
Start shallow in spring: smallmouth bass sit in 3 to 12 ft that time of year. Summer pushes them deeper, 8 to 25 ft, and winter fish settle into 8 to 25 ft. The spot to know is Main-lake point, a point in about 14 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 | Secondary point (9 ft) | Ned rig, Tube jig |
| Summer | 8 to 25 ft | dawn & dusk | Break off the point (24 ft) | Drop shot (goby/minnow), Ned rig |
| Fall | 8 to 25 ft | midday & dawn | Main-lake point (14 ft) | Jerkbait, Blade bait |
| Winter | 8 to 25 ft | midday | Break off the point (24 ft) | Blade bait, Hair jig |
The spring pattern is a shallow one: largemouth bass in 2 to 10 ft. As the season builds they drop to 8 to 20 ft, wintering in 8 to 25 ft. Top water on the chart: Shallow bay flat, a weed flat in the 2 ft range, prime in spring. Time it for early morning and the evening. Summer baits: a texas-rigged 10" worm or a deep-diving crankbait gets it done.
| Season | Depth | Best window | Start at | Go-to baits |
|---|---|---|---|---|
| Spring | 2 to 10 ft | dawn & dusk | Shallow bay flat (2 ft) | Spinnerbait, Chatterbait |
| Summer | 8 to 20 ft | dawn & dusk | Main-lake point (14 ft) | Texas-rigged 10" worm, Deep-diving crankbait |
| Fall | 4 to 15 ft | midday & dawn | Main-lake point (14 ft) | Squarebill crankbait (shad), Spinnerbait |
| Winter | 8 to 25 ft | midday | Break off the point (24 ft) | Blade bait, Jigging spoon |
Early season rock bass use the shallows, holding in 2 to 10 ft. Expect a summer slide to 5 to 20 ft, then a winter hold in 8 to 25 ft. Put Main-lake point first on the milk run — a point near 14 ft that grades prime for summer. In summer the feeding windows fall in the evening. Tie on a ned rig (small) or a marabou jig and you're in the game.
| Season | Depth | Best window | Start at | Go-to baits |
|---|---|---|---|---|
| Spring | 2 to 10 ft | midday & dawn | Secondary point (9 ft) | 1/16 oz jig + grub, Small inline spinner |
| Summer | 5 to 20 ft | dusk | Main-lake point (14 ft) | Ned rig (small), Marabou jig |
| Fall | 8 to 22 ft | midday | Main-lake point (14 ft) | Small tube jig, Inline spinner |
| Winter | 8 to 25 ft | midday | Deep basin (25 ft) | Tungsten jig + plastic, Small spoon + spike |
In spring, bluegill run shallow here, mostly 1 to 6 ft. Summer pushes them deeper, 4 to 15 ft, and winter fish settle into 10 to 25 ft. Shallow bay flat is the standout, a weed flat at roughly 2 ft, rated prime for spring bluegill. Time it for early morning and the evening. You won't need more than a small sponge spider (fly) or a micro tube jig most summer days.
| Season | Depth | Best window | Start at | Go-to baits |
|---|---|---|---|---|
| Spring | 1 to 6 ft | midday & dusk | Shallow bay flat (2 ft) | 1/32 oz jig + micro plastic, Tiny popper (evenings) |
| Summer | 4 to 15 ft | dawn & dusk | Shallow bay flat (2 ft) | Small sponge spider (fly), Micro tube jig |
| Fall | 6 to 18 ft | midday | Shallow bay flat (2 ft) | Micro jig + waxworm, Small spoon tipped |
| Winter | 10 to 25 ft | midday | Deep basin (25 ft) | Tungsten ice jig + plastic, Tiny spoon |
Thompson Lake also holds pumpkinseed (2 to 10 ft in summer), brown bullhead (3 to 12 ft in summer), channel catfish (8 to 25 ft in summer). Pick any of them on the map above for rated spots and bait picks.
Structure-wise the chart holds 6 features, led in depth by Deep basin at roughly 25 ft.
Access data: Michigan DNR — Michigan Boating Access Sites. Confirm conditions and fees locally before you launch.
Season dates, license requirements, and size and bag limits for Michigan waters are set by the Michigan DNR — and special regulations can apply to Thompson Lake specifically, so confirm the current rules before you fish.
Check the official Michigan fishing regulations →
Thompson Lake is about 25 ft (8 m) deep at its deepest point. The depth chart comes from published agency bathymetric survey data, so the contours are survey-derived rather than computer-modeled.
Anglers target yellow perch, northern pike, smallmouth bass, largemouth bass, rock bass, bluegill, pumpkinseed, brown bullhead, channel catfish on Thompson Lake. This isn't a survey of the lake — none is on record for it — but an informed estimate from the species listed for the nearest surveyed lakes in the region, filtered to this lake's depth and habitat.
Deep basin is the top-rated area: a deep basin in about 25 ft of water that rates prime for yellow perch in fall. The interactive chart above rates every spot for each species and season.
For yellow perch, 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.
Fishing on Thompson Lake 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.
Tamarack Lake 2 mi · Minnewaukan Lake 2 mi · Klinger Lake 3 mi · Omena Lake 4 mi · Aldrich Lake 5 mi · Prairie River Lake 5 mi · Sand Lake 6 mi · North Twin Lake 7 mi, IN · South Twin Lake 7 mi, IN · Sweet Lake 7 mi · Marl Lake 7 mi · Eberhard Lake 8 mi
See how Thompson Lake stacks up: best largemouth bass lakes in Michigan · best smallmouth bass lakes in Michigan · best northern pike lakes in Michigan · best bluegill lakes in Michigan
More water nearby: St. Joseph County fishing maps (21 charts). Browse all Michigan fishing maps or see every water on DepthScout. Bathymetry: published agency survey data. 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.