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197-acre lake in Hastings County, Ontario. The lake tops out around 42 ft. The depth chart comes from Ontario Ministry of Natural Resources and Forestry bathymetric survey data, so the contours are survey-derived rather than computer-modeled. Species by species, here's what the data says the year looks like.
Thomson Lake maps at 200 acres behind 4.5 miles of shoreline — one island included. A development index of 2.2 means a maze of bays and points: far more casting targets than a round bowl of the same size. About 84% of the surface sits shallower than 15 ft — that's the weed-and-bait zone. Call it 1.3 mi long by 0.6 mi wide at the broadest reach. Hastings County claims this one. Its nearest charted neighbour, Twin Sister L.s, is 2 mi to the southwest.
The spring pattern is a shallow one: yellow perch in 3 to 12 ft. As the season builds they drop to 10 to 30 ft, wintering in 15 to 35 ft. Top water on the chart: Break off the point, a drop-off in the 15 ft range, prime in summer. Time it for early morning. Summer baits: a drop-shot micro plastics or a small spoon tipped with worm gets it done.
| Season | Depth | Best window | Start at | Go-to baits |
|---|---|---|---|---|
| Spring | 3 to 12 ft | midday & dawn | Shallow bay flat (1 ft) | Small jig + curly tail, Perch-pattern micro crank |
| Summer | 10 to 30 ft | dawn | Break off the point (15 ft) | Drop-shot micro plastics, Small spoon tipped with worm |
| Fall | 12 to 35 ft | midday | Break off the point (15 ft) | Jigging spoon (small), Perch rig / spreader |
| Winter | 15 to 35 ft | midday & dawn | Deep basin (40 ft) | Tungsten jig + spikes, Rattle spoon (small) |
When the water first warms, smallmouth bass slide up into 3 to 12 ft. By summer they slide out to 10 to 30 ft, and by winter most fish are in 13 to 42 ft. If you only fish one area, make it Break off the point: a drop-off around 15 ft that scores prime in winter. In summer the feeding windows fall in early morning and the evening. Keep a drop shot (goby/minnow) or a ned rig rigged through the warm months.
| Season | Depth | Best window | Start at | Go-to baits |
|---|---|---|---|---|
| Spring | 3 to 12 ft | dawn & dusk | Main-lake point (1 ft) | Ned rig, Tube jig |
| Summer | 10 to 30 ft | dawn & dusk | Break off the point (15 ft) | Drop shot (goby/minnow), Ned rig |
| Fall | 8 to 25 ft | midday & dawn | Break off the point (15 ft) | Jerkbait, Blade bait |
| Winter | 13 to 42 ft | midday | Break off the point (15 ft) | Blade bait, Hair jig |
Come spring, look for largemouth bass tight to the bank in 2 to 10 ft. Expect a summer slide to 8 to 20 ft, then a winter hold in 15 to 35 ft. Start at Break off the point. It's a drop-off holding about 15 ft of water and rates prime come winter. Prime time lands in early morning and the evening. A texas-rigged 10" worm or a deep-diving crankbait is the honest summer answer here.
| Season | Depth | Best window | Start at | Go-to baits |
|---|---|---|---|---|
| Spring | 2 to 10 ft | dawn & dusk | Shallow bay flat (1 ft) | Spinnerbait, Chatterbait |
| Summer | 8 to 20 ft | dawn & dusk | Break off the point (15 ft) | Texas-rigged 10" worm, Deep-diving crankbait |
| Fall | 4 to 15 ft | midday & dawn | Main-lake point (1 ft) | Squarebill crankbait (shad), Spinnerbait |
| Winter | 15 to 35 ft | midday | Break off the point (15 ft) | Blade bait, Jigging spoon |
Start shallow in spring: rock bass sit in 2 to 10 ft that time of year. Warm water sends them out to 5 to 20 ft; cold water stacks them in 12 to 30 ft. Top water on the chart: Break off the point, a drop-off in the 15 ft range, prime in fall. Fish it in the evening and you'll meet the bite. Throw a ned rig (small) or a marabou jig until the fish tell you otherwise.
| Season | Depth | Best window | Start at | Go-to baits |
|---|---|---|---|---|
| Spring | 2 to 10 ft | midday & dawn | Main-lake point (1 ft) | 1/16 oz jig + grub, Small inline spinner |
| Summer | 5 to 20 ft | dusk | Break off the point (15 ft) | Ned rig (small), Marabou jig |
| Fall | 8 to 22 ft | midday | Break off the point (15 ft) | Small tube jig, Inline spinner |
| Winter | 12 to 30 ft | midday | Break off the point (15 ft) | Tungsten jig + plastic, Small spoon + spike |
Come spring, look for bluegill tight to the bank in 1 to 6 ft. They move out to 4 to 15 ft in summer and finish the year down in 10 to 25 ft. If you only fish one area, make it Shallow bay flat: a weed flat around 1 ft that scores prime in spring. Best bite is early morning and the evening. A small sponge spider (fly) or a micro tube jig is the honest summer answer here.
| Season | Depth | Best window | Start at | Go-to baits |
|---|---|---|---|---|
| Spring | 1 to 6 ft | midday & dusk | Shallow bay flat (1 ft) | 1/32 oz jig + micro plastic, Tiny popper (evenings) |
| Summer | 4 to 15 ft | dawn & dusk | Shallow bay flat (1 ft) | Small sponge spider (fly), Micro tube jig |
| Fall | 6 to 18 ft | midday | Break off the point (15 ft) | Micro jig + waxworm, Small spoon tipped |
| Winter | 10 to 25 ft | midday | Break off the point (15 ft) | Tungsten ice jig + plastic, Tiny spoon |
Start shallow in spring: pumpkinseed sit in 1 to 8 ft that time of year. Warm water sends them out to 2 to 10 ft; cold water stacks them in 6 to 18 ft. Top water on the chart: Shallow bay flat, a weed flat in the 1 ft range, prime in spring. Fish it in the evening and early morning and you'll meet the bite. Throw a micro tube or a sponge spider (fly) until the fish tell you otherwise.
| Season | Depth | Best window | Start at | Go-to baits |
|---|---|---|---|---|
| Spring | 1 to 8 ft | midday & dusk | Shallow bay flat (1 ft) | Micro jig under a float, Tiny beetle-spin |
| Summer | 2 to 10 ft | dusk & dawn | Shallow bay flat (1 ft) | Micro tube, Sponge spider (fly) |
| Fall | 4 to 14 ft | dusk & dawn | Shallow bay flat (1 ft) | Micro jig + waxworm, Small spoon tipped |
| Winter | 6 to 18 ft | dawn | Shallow feeding flat (20 ft) | Tungsten ice jig + plastic, Tiny spoon |
Thomson Lake carries 7 mapped structure features, topping out (or rather bottoming out) at Deep basin, about 40 ft down.
Season dates, license requirements, and size and bag limits for Ontario waters are set by the Ontario fishing regulations (FMZ summary) — and special regulations can apply to Thomson Lake specifically, so confirm the current rules before you fish.
Check the official Ontario fishing regulations →
Thomson Lake is about 42 ft (13 m) deep at its deepest point. The depth chart comes from Ontario Ministry of Natural Resources and Forestry bathymetric survey data, so the contours are survey-derived rather than computer-modeled.
Anglers target yellow perch, smallmouth bass, largemouth bass, rock bass, bluegill, pumpkinseed on Thomson Lake.
Break off the point is the top-rated area: a drop-off in about 15 ft of water that rates prime for smallmouth bass in winter. Scroll up to the map for the complete spot list by 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 Thomson Lake is regulated by the Ontario fishing regulations (FMZ summary). Check the official Ontario regulations for current license requirements, season dates, and size and bag limits — special regulations can apply to this specific water.
Twin Sister L.s 2 mi · Cordova Lake 6 mi · Lost Lake 7 mi · Crowe Lake 9 mi · Sandy Lake 9 mi · Oak Lake 9 mi · Belmont Lake 9 mi · Freen Lake 10 mi · Sebright Bay 10 mi · Round Lake 11 mi · Kasshabog Lake 11 mi · Lanes Lake 11 mi
See how Thomson Lake stacks up: best largemouth bass lakes in Ontario · best smallmouth bass lakes in Ontario · best bluegill lakes in Ontario · best yellow perch lakes in Ontario
More water nearby: Hastings County fishing maps (30 charts). Browse all Ontario 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.