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296-acre lake in Algoma District, Ontario. The lake tops out around 20 ft. The depth data here comes from the Ontario MNRF survey of 1979, a decades-old survey (a transect sounding survey). Species by species, here's what the data says the year looks like.
Rossmere Lake maps at 298 acres behind 4.7 miles of shoreline — one island included. A middling shoreline index (1.9) gives it some bays to work without being a maze. The shallow band under 15 ft claims about 89% of the surface — that's where the groceries are. Call it 1.5 mi long by 0.6 mi wide at the broadest reach. Algoma District claims this one. Mathers L. sits 3 mi north — the closest neighbouring chart.
Come spring, look for brook trout tight to the bank in 2 to 15 ft. They move out to 6 to 20 ft in summer and finish the year down in 3 to 20 ft. If you only fish one area, make it Deep basin: a deep basin around 20 ft that scores prime in summer. Best bite is early morning and the evening. A small spoon fished deep or a trolled lake-clear wobbler + worm is the honest summer answer here.
| Season | Depth | Best window | Start at | Go-to baits |
|---|---|---|---|---|
| Spring | 2 to 15 ft | dawn & dusk | Main-lake point (7 ft) | Small inline spinner (gold), Tiny spoon |
| Summer | 6 to 20 ft | dawn & dusk | Deep basin (20 ft) | Small spoon fished deep, Trolled lake-clear wobbler + worm |
| Fall | 2 to 15 ft | midday & dawn | Main-lake point (7 ft) | Small spoon (orange), Spinner |
| Winter | 3 to 20 ft | dawn | Deep basin (20 ft) | Small jigging spoon, Tungsten jig + plastic |
In spring, lake whitefish run shallow here, mostly 6 to 20 ft. Summer keeps them at 6 to 20 ft, and they winter in 6 to 20 ft. Summer lake whitefish concentrate at Deep basin, a prime-rated deep basin around 20 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 | 6 to 20 ft | midday & dawn | Break off the point (13 ft) | Small jig + waxworm, Blade bait (small) |
| Summer | 6 to 20 ft | dawn | Deep basin (20 ft) | Blade bait vertical, Small jigging spoon |
| Fall | 5 to 20 ft | dusk | Break off the point (13 ft) | Small spoon (gold), Jig + plastic larva |
| Winter | 6 to 20 ft | midday & dawn | Deep basin (20 ft) | Jigging spoon + bead chain, Tungsten jig + waxie |
In spring, cisco (lake herring) run shallow here, mostly 5 to 20 ft. Summer keeps them at 6 to 20 ft, and they winter in 6 to 20 ft. Spring cisco (lake herring) concentrate at Deep basin, a prime-rated deep basin around 20 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 | 5 to 20 ft | dawn & dusk | Deep basin (20 ft) | Small silver spoon, Tiny swim jig (white) |
| Summer | 6 to 20 ft | dawn | Deep basin (20 ft) | Vertical flutter spoon (small), Drop-shot micro plastic |
| Fall | 4 to 20 ft | dusk & dawn | Break off the point (13 ft) | Small casting spoon, Inline spinner (silver) |
| Winter | 6 to 20 ft | dawn | Deep basin (20 ft) | Small jigging spoon (glow/silver), Tungsten jig + minnow head |
The chart marks 6 structure features on Rossmere Lake; the deepest is Deep basin at about 20 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 Rossmere Lake specifically, so confirm the current rules before you fish.
Check the official Ontario fishing regulations →
Rossmere Lake is about 20 ft (6 m) deep at its deepest point. The depth data here comes from the Ontario MNRF survey of 1979, a decades-old survey (a transect sounding survey).
Anglers target brook trout, lake whitefish, cisco (lake herring) on Rossmere Lake.
Deep basin is the top-rated area: a deep basin in about 20 ft of water that rates prime for lake whitefish 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 Rossmere 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.
Mathers L. 3 mi · Quimby Lake 3 mi · Pistol Lake 3 mi · McGiverin Lake 3 mi · Little McGiverin L. 4 mi · Peak Lake 4 mi · Mink Lake 4 mi · Gullbeak Lake 5 mi · Slipper Lake 5 mi · Granary Lake 5 mi · Esten Lake 5 mi · Elliot L. 5 mi
See how Rossmere Lake stacks up: best brook trout lakes in Ontario · best lake whitefish lakes in Ontario · best cisco (lake herring) 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.