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231-acre lake in Thunder Bay District, Ontario. The lake tops out around 79 ft. The depth data here comes from a transect sounding survey by the Ontario MNRF. Below is the species-by-species picture, pulled from the same data the map uses.
Drawn out, this is 232 acres of water rimmed by 6.5 miles of bank, with 2 islands in the mix. That shoreline is heavily fingered (development index 3) — bays, points and pockets everywhere, which multiplies the fishable edge. The shallow band under 15 ft claims about 24% of the surface — that's where the groceries are. Tip to tip the water measures near 1.4 mi with a 0.7-mi widest point. You'll find it in Thunder Bay District. For a second option, Tunnel L. lies 2 mi north.
The spring pattern is a shallow one: lake trout in 10 to 40 ft. Midsummer fish sit out in 24 to 79 ft before dropping to 20 to 79 ft for winter. The spot to know is Deep basin, a deep basin in about 78 ft of water that rates prime for lake trout in summer. Plan around early morning in the warm months. Summer baits: a white tube jig (deep) or a magnum spoon on downrigger gets it done.
| Season | Depth | Best window | Start at | Go-to baits |
|---|---|---|---|---|
| Spring | 10 to 40 ft | dawn & dusk | Main-lake point (17 ft) | Casting spoon over shoals, Jerkbait (shallow) |
| Summer | 24 to 79 ft | dawn | Deep basin (78 ft) | White tube jig (deep), Magnum spoon on downrigger |
| Fall | 10 to 50 ft | dusk & dawn | Main-lake point (17 ft) | Heavy casting spoon, Jigging rap over reefs |
| Winter | 20 to 79 ft | dawn | Deep basin (78 ft) | White tube jig, Airplane jig |
Mountain Lake carries 6 mapped structure features, topping out (or rather bottoming out) at Deep basin, about 78 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 Mountain Lake specifically, so confirm the current rules before you fish.
Check the official Ontario fishing regulations →
Mountain Lake is about 79 ft (24 m) deep at its deepest point. The depth data here comes from a transect sounding survey by the Ontario MNRF.
Anglers target lake trout on Mountain Lake.
Deep basin is the top-rated area: a deep basin in about 78 ft of water that rates prime for lake trout in summer. Open the map above to see every rated spot for each 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 Mountain 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.
Tunnel L. 2 mi · Rushbay Lake 4 mi · Vale Lake 4 mi · Chimney Lake 7 mi · Collins Lake 7 mi · Clearwater Lake 8 mi · McLaurin Lake 8 mi · Nameiben Lake 8 mi · Bukemiga Lake 8 mi · Wigwasan Lake 8 mi · Mackenzie Lake 9 mi · Shawanabis Lake 10 mi
See how Mountain Lake stacks up: best lake trout 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.