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1,497-acre lake in Thunder Bay District, Ontario. The lake tops out around 118 ft. The depth data here comes from the Ontario MNRF survey of 1978, a decades-old survey (a transect sounding survey). Here's the year, species by species, as the scoring engine sees it.
The drawn water covers 1,504 acres wrapped in 16 miles of bank, with 6 islands in the mix. That shoreline is heavily fingered (development index 2.9) — bays, points and pockets everywhere, which multiplies the fishable edge. Roughly 40% of the water is 15 ft or less, the band where the food chain lives. Tip to tip the water measures near 4 mi with a 1.7-mi widest point. Thunder Bay District claims this one. Its nearest charted neighbour, Clamp Lake, is 2 mi to the northeast.
Spring lake trout on Castle Lake hold shallow, usually 10 to 40 ft. They move out to 35 to 118 ft in summer and finish the year down in 20 to 80 ft. Put Deep basin first on the milk run — a deep basin near 118 ft that grades prime for summer. The feeding windows run early morning. The summer box starts with a white tube jig (deep) or a magnum spoon on downrigger.
| Season | Depth | Best window | Start at | Go-to baits |
|---|---|---|---|---|
| Spring | 10 to 40 ft | dawn & dusk | Main-lake point (1 ft) | Casting spoon over shoals, Jerkbait (shallow) |
| Summer | 35 to 118 ft | dawn | Deep basin (118 ft) | White tube jig (deep), Magnum spoon on downrigger |
| Fall | 10 to 50 ft | dusk & dawn | Main-lake point (1 ft) | Heavy casting spoon, Jigging rap over reefs |
| Winter | 20 to 80 ft | dawn | Break off the point (81 ft) | White tube jig, Airplane jig |
In spring, lake whitefish run shallow here, mostly 15 to 45 ft. Midsummer fish sit out in 40 to 90 ft before dropping to 25 to 70 ft for winter. Summer lake whitefish concentrate at Break off the point, a prime-rated drop-off around 81 ft. Fish it in early morning and you'll meet the bite. You won't need more than a blade bait vertical or a small jigging spoon most summer days.
| Season | Depth | Best window | Start at | Go-to baits |
|---|---|---|---|---|
| Spring | 15 to 45 ft | midday & dawn | Shallow feeding flat (33 ft) | Small jig + waxworm, Blade bait (small) |
| Summer | 40 to 90 ft | dawn | Break off the point (81 ft) | Blade bait vertical, Small jigging spoon |
| Fall | 8 to 30 ft | dusk | open water | Small spoon (gold), Jig + plastic larva |
| Winter | 25 to 70 ft | midday & dawn | Shallow feeding flat (33 ft) | Jigging spoon + bead chain, Tungsten jig + waxie |
In spring, cisco (lake herring) run shallow here, mostly 10 to 40 ft. Midsummer fish sit out in 40 to 80 ft before dropping to 20 to 60 ft for winter. Summer cisco (lake herring) concentrate at Break off the point, a good-rated drop-off around 81 ft. Fish it in early morning and you'll meet the bite. You won't need more than a vertical flutter spoon (small) or a drop-shot micro plastic most summer days.
| Season | Depth | Best window | Start at | Go-to baits |
|---|---|---|---|---|
| Spring | 10 to 40 ft | dawn & dusk | Deep basin (118 ft) | Small silver spoon, Tiny swim jig (white) |
| Summer | 40 to 80 ft | dawn | Break off the point (81 ft) | Vertical flutter spoon (small), Drop-shot micro plastic |
| Fall | 5 to 25 ft | dusk & dawn | open water | Small casting spoon, Inline spinner (silver) |
| Winter | 20 to 60 ft | dawn | Deep basin (118 ft) | Small jigging spoon (glow/silver), Tungsten jig + minnow head |
In spring, yellow perch run shallow here, mostly 3 to 12 ft. Summer pushes them deeper, 10 to 30 ft, and winter fish settle into 15 to 35 ft. Shallow bay flat is the standout, a weed flat at roughly 1 ft, rated prime for spring yellow perch. Time it for early morning. You won't need more than a drop-shot micro plastics or a small spoon tipped with worm most summer days.
| 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 | Feeding flat (31 ft) | Drop-shot micro plastics, Small spoon tipped with worm |
| Fall | 12 to 35 ft | midday | Deep basin (118 ft) | Jigging spoon (small), Perch rig / spreader |
| Winter | 15 to 35 ft | midday & dawn | Shallow feeding flat (33 ft) | Tungsten jig + spikes, Rattle spoon (small) |
Early season northern pike use the shallows, holding in 2 to 8 ft. Expect a summer slide to 8 to 20 ft, then a winter hold 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. In summer the feeding windows fall in early morning and the evening. Tie on a bucktail or a weedless spoon over cabbage and you're in the game.
| 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 bay flat (1 ft) | Bucktail, Weedless spoon over cabbage |
| Fall | 6 to 18 ft | midday & dawn | Shallow bay flat (1 ft) | Big rubber (Bull Dawg style), Husky-style jerkbait |
| Winter | 5 to 15 ft | midday | Shallow bay flat (1 ft) | Tip-ups, Large jigging spoon |
Spring burbot on Castle Lake hold shallow, usually 25 to 70 ft. They move out to 35 to 118 ft in summer and finish the year down in 15 to 60 ft. Put Deep basin first on the milk run — a deep basin near 118 ft that grades prime for summer. The feeding windows run after dark and midday. The summer box starts with a heavy jig + cut bait.
| Season | Depth | Best window | Start at | Go-to baits |
|---|---|---|---|---|
| Spring | 25 to 70 ft | night & dusk | Deep basin (118 ft) | Glow jigging spoon + cut bait, Rattle bait (dark) |
| Summer | 35 to 118 ft | night & midday | Deep basin (118 ft) | Heavy jig + cut bait |
| Fall | 30 to 80 ft | night & dusk | Break off the point (81 ft) | Glow spoon + minnow head, Blade bait (slow) |
| Winter | 15 to 60 ft | night & dusk | Deep basin (118 ft) | Glow tungsten + cut bait, Rattle spoon + minnow head |
8 pieces of structure are mapped here — Deep basin, around 118 ft, is the deepest of them.
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 Castle Lake specifically, so confirm the current rules before you fish.
Check the official Ontario fishing regulations →
Castle Lake is about 118 ft (36 m) deep at its deepest point. The depth data here comes from the Ontario MNRF survey of 1978, a decades-old survey (a transect sounding survey).
Anglers target lake trout, lake whitefish, cisco (lake herring), yellow perch, northern pike, burbot on Castle Lake.
Deep basin is the top-rated area: a deep basin in about 118 ft of water that rates prime for lake trout in summer. The map above holds the full rated-spot list for every species and season.
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.
Fishing on Castle 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.
Clamp Lake 2 mi · Walkover Lake 3 mi · Snowshoe Lake 4 mi · Wabinosh Lake 6 mi · Inspiration Lake 8 mi · Waweig Lake 10 mi · McLaurin Lake 11 mi · Chimney Lake 12 mi · Mackenzie Lake 12 mi · Jojo Lake 12 mi · Nameiben Lake 12 mi · Clearwater Lake 13 mi
See how Castle Lake stacks up: best northern pike lakes in Ontario · best yellow perch lakes in Ontario · best lake trout lakes in Ontario · best lake whitefish lakes in Ontario
More water nearby: Thunder Bay District fishing maps (662 charts). Browse all Ontario 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.