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409-acre lake in Thunder Bay District, Ontario. The lake tops out around 64 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 the Ontario MNRF survey of 1979, a decades-old survey (an MNRF lake survey). Here's the year, species by species, as the scoring engine sees it.
Cornish Lake maps at 407 acres behind 7.5 miles of shoreline. The 2.6 development index tells the story — a convoluted bank whose fishable edge far outruns the acreage. The shallow band under 15 ft claims about 87% of the surface — that's where the groceries are. Figure 2.3 mi of water from one end to the other, 1.1 mi at the beam. It sits in Thunder Bay District. Caragana Lake sits 8 mi west — the closest neighbouring chart.
Spring puts lake whitefish in skinny water — 15 to 45 ft is the zone. As the season builds they drop to 19 to 64 ft, wintering in 19 to 64 ft. Summer lake whitefish concentrate at Deep basin, a prime-rated deep basin around 40 ft. Warm-month bites cluster around early morning. A blade bait vertical or a small jigging spoon 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 | 15 to 45 ft | midday & dawn | Shallow feeding flat (13 ft) | Small jig + waxworm, Blade bait (small) |
| Summer | 19 to 64 ft chart-limited; documented 40 to 90 ft | dawn | Deep basin (40 ft) | Blade bait vertical, Small jigging spoon |
| Fall | 8 to 30 ft | dusk | Main-lake point (6 ft) | Small spoon (gold), Jig + plastic larva |
| Winter | 19 to 64 ft chart-limited; documented 25 to 70 ft | midday & dawn | Deep basin (40 ft) | Jigging spoon + bead chain, Tungsten jig + waxie |
Spring puts cisco (lake herring) in skinny water — 10 to 40 ft is the zone. As the season builds they drop to 19 to 64 ft, wintering in 20 to 60 ft. Spring cisco (lake herring) concentrate at Deep basin, a prime-rated deep basin around 40 ft. Warm-month bites cluster around early morning. A vertical flutter spoon (small) or a drop-shot micro plastic 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 | 10 to 40 ft | dawn & dusk | Deep basin (40 ft) | Small silver spoon, Tiny swim jig (white) |
| Summer | 19 to 64 ft chart-limited; documented 40 to 80 ft | dawn | Deep basin (40 ft) | Vertical flutter spoon (small), Drop-shot micro plastic |
| Fall | 5 to 25 ft | dusk & dawn | Break off the point (2 ft) | Small casting spoon, Inline spinner (silver) |
| Winter | 20 to 60 ft | dawn | Deep basin (40 ft) | Small jigging spoon (glow/silver), Tungsten jig + minnow head |
Start shallow in spring: walleye sit in 4 to 15 ft that time of year. Warm water sends them out to 15 to 35 ft; cold water stacks them in 20 to 40 ft. Top water on the chart: Deep basin, a deep basin in the 40 ft range, prime in winter. Fish it in the evening and early morning and you'll meet the bite. Throw a crawler harness on bottom bouncer or a deep crankbait (trolled) until the fish tell you otherwise.
| Season | Depth | Best window | Start at | Go-to baits |
|---|---|---|---|---|
| Spring | 4 to 15 ft | dusk & dawn | Main-lake point (6 ft) | 1/8 oz jig + minnow, Hair jig |
| Summer | 15 to 35 ft | dusk & dawn | Shallow feeding flat (13 ft) | Crawler harness on bottom bouncer, Deep crankbait (trolled) |
| Fall | 12 to 40 ft | dusk & night | Deep basin (40 ft) | Jigging rap, Jig + big minnow |
| Winter | 20 to 40 ft | dusk & dawn | Deep basin (40 ft) | Jigging spoon + minnow head, Rattle bait |
Spring puts yellow perch in skinny water — 3 to 12 ft is the zone. Warm water sends them out to 10 to 30 ft; cold water stacks them in 15 to 35 ft. Deep basin is the standout, a deep basin at roughly 40 ft, rated prime for fall yellow perch. Plan around early morning in the warm months. A drop-shot micro plastics or a small spoon tipped with worm covers the summer program.
| 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 | Shallow feeding flat (13 ft) | Drop-shot micro plastics, Small spoon tipped with worm |
| Fall | 12 to 35 ft | midday | Deep basin (40 ft) | Jigging spoon (small), Perch rig / spreader |
| Winter | 15 to 35 ft | midday & dawn | Deep basin (40 ft) | Tungsten jig + spikes, Rattle spoon (small) |
Spring northern pike on Cornish Lake hold shallow, usually 2 to 8 ft. They move out to 8 to 20 ft in summer and finish the year down in 5 to 15 ft. Put Shallow bay flat first on the milk run — a weed flat near 1 ft that grades prime for spring. The feeding windows run early morning and the evening. The summer box starts with a bucktail or a weedless spoon over cabbage.
| Season | Depth | Best window | Start at | Go-to baits |
|---|---|---|---|---|
| Spring | 2 to 8 ft | midday & dawn | Shallow bay flat (1 ft) | #5 inline spinner, Spoon (red/white) |
| Summer | 8 to 20 ft | dawn & dusk | Shallow feeding flat (13 ft) | Bucktail, Weedless spoon over cabbage |
| Fall | 6 to 18 ft | midday & dawn | Main-lake point (6 ft) | Big rubber (Bull Dawg style), Husky-style jerkbait |
| Winter | 5 to 15 ft | midday | Shallow feeding flat (13 ft) | Tip-ups, Large jigging spoon |
The chart marks 7 structure features on Cornish Lake; the deepest is Deep basin at about 40 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 Cornish Lake specifically, so confirm the current rules before you fish.
Check the official Ontario fishing regulations →
Cornish Lake is about 64 ft (20 m) deep at its deepest point. The depth data here comes from the Ontario MNRF survey of 1979, a decades-old survey (an MNRF lake survey).
Anglers target lake whitefish, cisco (lake herring), walleye, yellow perch, northern pike on Cornish Lake.
Deep basin is the top-rated area: a deep basin in about 40 ft of water that rates prime for lake whitefish in summer. Every other rated spot, per species and season, is on the map above.
For lake whitefish, 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 Cornish 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.
Caragana Lake 8 mi · Kagiano Lake 8 mi · Killala Lake 9 mi · Little Pic Lake 11 mi · Steel Lake 11 mi · Campcot Lake 12 mi · Eaglecrest Lake 13 mi · Sun Lake 14 mi · Esker Lake 18 mi · Foxtrap Lake 20 mi · Hob Lake 20 mi · Catlonite Lake 21 mi
See how Cornish Lake stacks up: best walleye lakes in Ontario · best northern pike lakes in Ontario · best yellow perch lakes in Ontario · best lake whitefish lakes in Ontario
More water nearby: Thunder Bay District fishing maps (662 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.