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78-acre lake in Muskoka District Municipality, Ontario. The lake tops out around 80 ft. The depth data here comes from the Ontario MNRF survey of 1970, a decades-old survey (a transect sounding survey). Below is the species-by-species picture, pulled from the same data the map uses.
The outline encloses 78 acres, worked by 2.6 miles of shoreline. A middling shoreline index (2.1) gives it some bays to work without being a maze. About 14% of the surface sits shallower than 15 ft — that's the weed-and-bait zone. Tip to tip the water measures near 0.8 mi with a 0.3-mi widest point. Muskoka District Municipality claims this one. If the bite dies, Raven Lake is 2 mi to the northeast.
Spring splake on Grindstone Lake hold shallow, usually 5 to 25 ft. They move out to 25 to 60 ft in summer and finish the year down in 10 to 45 ft. Put Break off the point first on the milk run — a drop-off near 27 ft that grades prime for summer. The feeding windows run early morning and the evening. The summer box starts with a trolled spoon at the thermocline or a white tube jig (deep).
| Season | Depth | Best window | Start at | Go-to baits |
|---|---|---|---|---|
| Spring | 5 to 25 ft | dawn & dusk | Secondary point (14 ft) | Small casting spoon (gold/orange), Inline spinner |
| Summer | 25 to 60 ft | dawn & dusk | Break off the point (27 ft) | Trolled spoon at the thermocline, White tube jig (deep) |
| Fall | 10 to 35 ft | dawn & dusk | Secondary point (14 ft) | Casting spoon, Jerkbait |
| Winter | 10 to 45 ft | dawn | Break off the point (27 ft) | Jigging spoon tipped with minnow head, Small white tube |
Spring puts yellow perch in skinny water — 3 to 12 ft is the zone. As the season builds they drop to 10 to 30 ft, wintering in 15 to 35 ft. Summer yellow perch concentrate at Break off the point, a prime-rated drop-off around 27 ft. Warm-month bites cluster around early morning. 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 (11 ft) | Small jig + curly tail, Perch-pattern micro crank |
| Summer | 10 to 30 ft | dawn | Break off the point (27 ft) | Drop-shot micro plastics, Small spoon tipped with worm |
| Fall | 12 to 35 ft | midday | Break off the point (27 ft) | Jigging spoon (small), Perch rig / spreader |
| Winter | 15 to 35 ft | midday & dawn | Break off the point (27 ft) | Tungsten jig + spikes, Rattle spoon (small) |
Spring smallmouth bass on Grindstone Lake hold shallow, usually 3 to 12 ft. By summer they slide out to 10 to 30 ft, and by winter most fish are in 20 to 45 ft. The chart's best answer is Secondary point — point, 14 ft, prime for fall. Prime time lands in early morning and the evening. The summer box starts with a drop shot (goby/minnow) or a ned rig.
| Season | Depth | Best window | Start at | Go-to baits |
|---|---|---|---|---|
| Spring | 3 to 12 ft | dawn & dusk | Secondary point (14 ft) | Ned rig, Tube jig |
| Summer | 10 to 30 ft | dawn & dusk | Break off the point (27 ft) | Drop shot (goby/minnow), Ned rig |
| Fall | 8 to 25 ft | midday & dawn | Secondary point (14 ft) | Jerkbait, Blade bait |
| Winter | 20 to 45 ft | midday | Break off the point (27 ft) | Blade bait, Hair jig |
Spring puts pumpkinseed in skinny water — 1 to 8 ft is the zone. Warm water sends them out to 2 to 10 ft; cold water stacks them in 6 to 18 ft. Back-bay flat is the standout, a feeding flat at roughly 6 ft, rated prime for spring pumpkinseed. Plan around the evening and early morning in the warm months. A micro tube or a sponge spider (fly) covers the summer program.
| Season | Depth | Best window | Start at | Go-to baits |
|---|---|---|---|---|
| Spring | 1 to 8 ft | midday & dusk | Back-bay flat (6 ft) | Micro jig under a float, Tiny beetle-spin |
| Summer | 2 to 10 ft | dusk & dawn | Back-bay flat (6 ft) | Micro tube, Sponge spider (fly) |
| Fall | 4 to 14 ft | dusk & dawn | Shallow bay flat (11 ft) | Micro jig + waxworm, Small spoon tipped |
| Winter | 6 to 18 ft | dawn | Shallow bay flat (11 ft) | Tungsten ice jig + plastic, Tiny spoon |
6 pieces of structure are mapped here — Deep basin, around 80 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 Grindstone Lake specifically, so confirm the current rules before you fish.
Check the official Ontario fishing regulations →
Grindstone Lake is about 80 ft (24 m) deep at its deepest point. The depth data here comes from the Ontario MNRF survey of 1970, a decades-old survey (a transect sounding survey).
Anglers target splake, yellow perch, smallmouth bass, pumpkinseed on Grindstone Lake.
Break off the point is the top-rated area: a drop-off in about 27 ft of water that rates prime for splake in summer. The map above holds the full rated-spot list for every species and season.
For splake, 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 Grindstone 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.
Raven Lake 2 mi · Shoe Lake 2 mi · Black Lake 3 mi · Avery Lake 3 mi · Blue Chalk Lake 3 mi · Dan Lake 3 mi · Deer Lake 3 mi · Nehemiah Lake 3 mi · Red Chalk Lake 3 mi · Paint Lake 4 mi · Horners Lake 4 mi · Lake St. Nora 4 mi
See how Grindstone Lake stacks up: best smallmouth bass lakes in Ontario · best yellow perch lakes in Ontario · best splake lakes in Ontario · best pumpkinseed lakes in Ontario
More water nearby: Muskoka District Municipality fishing maps (276 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.