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551-acre lake in Algoma District, Ontario. The lake tops out around 98 ft. The depth data here comes from the Ontario MNRF survey of 2025 (an MNRF lake survey). Species by species, here's what the data says the year looks like.
Drawn out, this is 554 acres of water rimmed by 10.2 miles of bank — 4 islands included. That shoreline is heavily fingered (development index 3.1) — bays, points and pockets everywhere, which multiplies the fishable edge. About 10% of the surface sits shallower than 15 ft — that's the weed-and-bait zone. Tip to tip the water measures near 2 mi with a 1.2-mi widest point. You'll find it in Algoma District. Closest neighbour on DepthScout: Chipman Lake, 1 mi northeast of here.
In spring, brook trout run shallow here, mostly 2 to 15 ft. Summer pushes them deeper, 10 to 30 ft, and winter fish settle into 3 to 20 ft. Shallow bay flat is the standout, a feeding flat at roughly 2 ft, rated good for spring brook trout. Time it for early morning and the evening. You won't need more than a small spoon fished deep or a trolled lake-clear wobbler + worm most summer days.
| Season | Depth | Best window | Start at | Go-to baits |
|---|---|---|---|---|
| Spring | 2 to 15 ft | dawn & dusk | Shallow bay flat (2 ft) | Small inline spinner (gold), Tiny spoon |
| Summer | 10 to 30 ft | dawn & dusk | open water | Small spoon fished deep, Trolled lake-clear wobbler + worm |
| Fall | 2 to 15 ft | midday & dawn | open water | Small spoon (orange), Spinner |
| Winter | 3 to 20 ft | dawn | Back-bay flat (12 ft) | Small jigging spoon, Tungsten jig + plastic |
Spring puts lake trout in skinny water — 10 to 40 ft is the zone. Warm water sends them out to 29 to 98 ft; cold water stacks them in 20 to 80 ft. Deep basin is the standout, a deep basin at roughly 98 ft, rated prime for summer lake trout. Plan around early morning in the warm months. A white tube jig (deep) or a magnum spoon on downrigger covers the summer program.
| Season | Depth | Best window | Start at | Go-to baits |
|---|---|---|---|---|
| Spring | 10 to 40 ft | dawn & dusk | Secondary point (23 ft) | Casting spoon over shoals, Jerkbait (shallow) |
| Summer | 29 to 98 ft | dawn | Deep basin (98 ft) | White tube jig (deep), Magnum spoon on downrigger |
| Fall | 10 to 50 ft | dusk & dawn | Main-lake point (46 ft) | Heavy casting spoon, Jigging rap over reefs |
| Winter | 20 to 80 ft | dawn | Break off the point (91 ft) | White tube jig, Airplane jig |
Early season lake whitefish use the shallows, holding in 15 to 45 ft. Summer is a 40 to 90 ft game here, winter a 25 to 70 ft one. The chart's best answer is Deep basin — deep basin, 98 ft, prime for summer. Best bite is early morning. Tie on a blade bait vertical or a small jigging spoon and you're in the game.
| Season | Depth | Best window | Start at | Go-to baits |
|---|---|---|---|---|
| Spring | 15 to 45 ft | midday & dawn | Shallow feeding flat (25 ft) | Small jig + waxworm, Blade bait (small) |
| Summer | 40 to 90 ft | dawn | Deep basin (98 ft) | Blade bait vertical, Small jigging spoon |
| Fall | 8 to 30 ft | dusk | Secondary point (23 ft) | Small spoon (gold), Jig + plastic larva |
| Winter | 25 to 70 ft | midday & dawn | Shallow feeding flat (25 ft) | Jigging spoon + bead chain, Tungsten jig + waxie |
Early season cisco (lake herring) use the shallows, holding in 10 to 40 ft. Summer is a 40 to 80 ft game here, winter a 20 to 60 ft one. The chart's best answer is Deep basin — deep basin, 98 ft, good for summer. Best bite is early morning. Tie on a vertical flutter spoon (small) or a drop-shot micro plastic and you're in the game.
| Season | Depth | Best window | Start at | Go-to baits |
|---|---|---|---|---|
| Spring | 10 to 40 ft | dawn & dusk | Deep basin (98 ft) | Small silver spoon, Tiny swim jig (white) |
| Summer | 40 to 80 ft | dawn | Deep basin (98 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 (98 ft) | Small jigging spoon (glow/silver), Tungsten jig + minnow head |
Come spring, look for yellow perch tight to the bank in 3 to 12 ft. They move out to 10 to 30 ft in summer and finish the year down in 15 to 35 ft. If you only fish one area, make it Back-bay flat: a feeding flat around 12 ft that scores prime in spring. Best bite is 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 | Back-bay flat (12 ft) | Small jig + curly tail, Perch-pattern micro crank |
| Summer | 10 to 30 ft | dawn | Back-bay flat (12 ft) | Drop-shot micro plastics, Small spoon tipped with worm |
| Fall | 12 to 35 ft | midday | Deep basin (98 ft) | Jigging spoon (small), Perch rig / spreader |
| Winter | 15 to 35 ft | midday & dawn | Shallow feeding flat (25 ft) | Tungsten jig + spikes, Rattle spoon (small) |
Spring puts burbot in skinny water — 25 to 70 ft is the zone. Warm water sends them out to 29 to 98 ft; cold water stacks them in 15 to 60 ft. Deep basin is the standout, a deep basin at roughly 98 ft, rated prime for summer burbot. Plan around after dark and midday in the warm months. A heavy jig + cut bait covers the summer program.
| Season | Depth | Best window | Start at | Go-to baits |
|---|---|---|---|---|
| Spring | 25 to 70 ft | night & dusk | Deep basin (98 ft) | Glow jigging spoon + cut bait, Rattle bait (dark) |
| Summer | 29 to 98 ft | night & midday | Deep basin (98 ft) | Heavy jig + cut bait |
| Fall | 30 to 80 ft | night & dusk | Deep basin (98 ft) | Glow spoon + minnow head, Blade bait (slow) |
| Winter | 15 to 60 ft | night & dusk | Deep basin (98 ft) | Glow tungsten + cut bait, Rattle spoon + minnow head |
8 pieces of structure are mapped here — Deep basin, around 98 ft, is the deepest of them.
Access data: Land Information Ontario — Fishing Access Point. Confirm conditions and fees locally before you launch.
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 McMahon Lake specifically, so confirm the current rules before you fish.
Check the official Ontario fishing regulations →
McMahon Lake is about 98 ft (30 m) deep at its deepest point. The depth data here comes from the Ontario MNRF survey of 2025 (an MNRF lake survey).
Anglers target brook trout, lake trout, lake whitefish, cisco (lake herring), yellow perch, burbot on McMahon Lake.
Deep basin is the top-rated area: a deep basin in about 98 ft of water that rates prime for lake trout in summer. Scroll up to the map for the complete spot list by species and season.
For brook trout, the summer bite is best in early morning and the evening. Each species page section below lists the seasonal windows, and the map shows a live NOW badge when you're inside one.
Fishing on McMahon 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.
Chipman Lake 1 mi · Bass Lake 2 mi · Patten Lake 2 mi · Hugli Lake 2 mi · Hart Lake 2 mi · Grant Lake 3 mi · Two Horse Lake 4 mi · Hoath Lake 4 mi · One Horse Lake 4 mi · Tarpaper Lake 4 mi · Peter Lake 4 mi · Solar Lake 5 mi
See how McMahon Lake stacks up: best yellow perch lakes in Ontario · best lake trout lakes in Ontario · best brook trout lakes in Ontario · best lake whitefish lakes in Ontario
More water nearby: Algoma District fishing maps (1026 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.