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157-acre lake in Algoma District, Ontario. The lake tops out around 10 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. The depth data here comes from a transect sounding survey by the Ontario MNRF. Here is how the season plays out for each species, straight from the data behind the map.
The outline encloses 157 acres, worked by 4.3 miles of shoreline. With a shoreline index of 2.4, this water is all arms and coves — edge habitat well beyond its acreage. All of it is shallow-zone water — under ~15 ft across the entire basin, so the food chain has the run of the place. The basin spans about 1.8 mi end to end and 0.4 mi across at its widest. It sits in Algoma District. Its nearest charted neighbour, Oscar Lake, is 1 mi to the east.
These fish are listed in an exact-water agency record as forage or ecological context. They are not target-species profiles and do not affect DepthScout's Prime, Good, or Fair spot ratings.
Official Ontario MNRF Fish ON-Line record. The listing documents source-recorded presence, not present abundance or guaranteed catchability.
Spring puts walleye in skinny water — 3 to 10 ft is the zone. Summer fish stay in 3 to 10 ft, and winter fish hold in 3 to 10 ft. Break off the point is the standout, a drop-off at roughly 9 ft, rated prime for fall walleye. Plan around the evening and early morning in the warm months. A crawler harness on bottom bouncer or a deep crankbait (trolled) covers the summer program.
Depth note: when a documented seasonal range extends below this chart, the table shows the deepest mapped working water, not a verified holding depth.
| Season | Depth | Best window | Start at | Go-to baits |
|---|---|---|---|---|
| Spring | 3 to 10 ft chart-limited; documented 4 to 15 ft | dusk & dawn | Main-lake point (5 ft) | 1/8 oz jig + minnow, Hair jig |
| Summer | 3 to 10 ft chart-limited; documented 15 to 35 ft | dusk & dawn | Break off the point (9 ft) | Crawler harness on bottom bouncer, Deep crankbait (trolled) |
| Fall | 3 to 10 ft chart-limited; documented 12 to 40 ft | dusk & night | Break off the point (9 ft) | Jigging rap, Jig + big minnow |
| Winter | 3 to 10 ft chart-limited; documented 20 to 40 ft | dusk & dawn | Deep basin (10 ft) | Jigging spoon + minnow head, Rattle bait |
Start shallow in spring: yellow perch sit in 3 to 10 ft that time of year. They don't go far with the seasons — 3 to 10 ft covers summer, 3 to 10 ft covers winter. Top water on the chart: Shallow bay flat, a weed flat in the 3 ft range, prime in spring. Fish it in early morning and you'll meet the bite. Throw a drop-shot micro plastics or a small spoon tipped with worm until the fish tell you otherwise.
Depth note: when a documented seasonal range extends below this chart, the table shows the deepest mapped working water, not a verified holding depth.
| Season | Depth | Best window | Start at | Go-to baits |
|---|---|---|---|---|
| Spring | 3 to 10 ft chart-limited; documented 3 to 12 ft | midday & dawn | Shallow bay flat (3 ft) | Small jig + curly tail, Perch-pattern micro crank |
| Summer | 3 to 10 ft chart-limited; documented 10 to 30 ft | dawn | Deep basin (10 ft) | Drop-shot micro plastics, Small spoon tipped with worm |
| Fall | 3 to 10 ft chart-limited; documented 12 to 35 ft | midday | Deep basin (10 ft) | Jigging spoon (small), Perch rig / spreader |
| Winter | 3 to 10 ft chart-limited; documented 15 to 35 ft | midday & dawn | Deep basin (10 ft) | Tungsten jig + spikes, Rattle spoon (small) |
Come spring, look for northern pike tight to the bank in 2 to 8 ft. They move out to 3 to 10 ft in summer and finish the year down in 3 to 10 ft. If you only fish one area, make it Shallow bay flat: a weed flat around 3 ft that scores prime in spring. Best bite is early morning and the evening. A bucktail or a weedless spoon over cabbage is the honest summer answer here.
Depth note: when a documented seasonal range extends below this chart, the table shows the deepest mapped working water, not a verified holding depth.
| Season | Depth | Best window | Start at | Go-to baits |
|---|---|---|---|---|
| Spring | 2 to 8 ft | midday & dawn | Shallow bay flat (3 ft) | #5 inline spinner, Spoon (red/white) |
| Summer | 3 to 10 ft chart-limited; documented 8 to 20 ft | dawn & dusk | Shallow bay flat (3 ft) | Bucktail, Weedless spoon over cabbage |
| Fall | 3 to 10 ft chart-limited; documented 6 to 18 ft | midday & dawn | Shallow bay flat (3 ft) | Big rubber (Bull Dawg style), Husky-style jerkbait |
| Winter | 3 to 10 ft chart-limited; documented 5 to 15 ft | midday | Shallow bay flat (3 ft) | Tip-ups, Large jigging spoon |
Come spring, look for burbot tight to the bank in 3 to 10 ft. Through summer count on 3 to 10 ft; the winter hold is 3 to 10 ft. Start at Deep basin. It's a deep basin holding about 10 ft of water and rates prime come spring. Prime time lands in after dark and midday. A heavy jig + cut bait is the honest summer answer here.
Depth note: when a documented seasonal range extends below this chart, the table shows the deepest mapped working water, not a verified holding depth.
| Season | Depth | Best window | Start at | Go-to baits |
|---|---|---|---|---|
| Spring | 3 to 10 ft chart-limited; documented 25 to 70 ft | night & dusk | Deep basin (10 ft) | Glow jigging spoon + cut bait, Rattle bait (dark) |
| Summer | 3 to 10 ft chart-limited; documented 50 to 120 ft | night & midday | Deep basin (10 ft) | Heavy jig + cut bait |
| Fall | 3 to 10 ft chart-limited; documented 30 to 80 ft | night & dusk | Deep basin (10 ft) | Glow spoon + minnow head, Blade bait (slow) |
| Winter | 3 to 10 ft chart-limited; documented 15 to 60 ft | night & dusk | Deep basin (10 ft) | Glow tungsten + cut bait, Rattle spoon + minnow head |
Count 6 structure marks on this chart. The deepest, Deep basin, sits near 10 ft.
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 Thom Lake specifically, so confirm the current rules before you fish.
Check the official Ontario fishing regulations →
Thom Lake is about 10 ft (3 m) deep at its deepest point. The depth data here comes from a transect sounding survey by the Ontario MNRF.
Anglers target walleye, yellow perch, northern pike, burbot on Thom Lake.
Break off the point is the top-rated area: a drop-off in about 9 ft of water that rates prime for walleye in fall. Open the map above to see every rated spot for each species and season.
For walleye, the summer bite is best in the evening and 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 Thom 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.
Oscar Lake 1 mi · Cooper Lake 3 mi · Powell Lake 3 mi · Bourinot Lake 5 mi · South Moosehorn Lake 5 mi · Graveyard Lake 7 mi · Penelton Lake 9 mi · Lepp Lake 10 mi · Usnac Lake 11 mi · Opasatika Lake 11 mi · Rufus Lake 11 mi · Opasakita Lake 12 12 mi
See how Thom Lake stacks up: best walleye lakes in Ontario · best northern pike lakes in Ontario · best yellow perch lakes in Ontario · best burbot lakes in Ontario
More water nearby: Algoma District fishing maps (1026 charts). Browse all Ontario fishing maps. 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.