Sign inSign up free Sign inSign up free Sign inSign up freeLake depth chart
Today's read
Recent public catches load as you reach this section.
178-acre lake in Rainy River District, Ontario. The lake tops out around 78 ft. The depth chart comes from Ontario Ministry of Natural Resources and Forestry bathymetric survey data, so the contours are survey-derived rather than computer-modeled. 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.
The drawn water covers 179 acres wrapped in 5 miles of bank, with a single island in the mix. A development index of 2.7 means a maze of bays and points: far more casting targets than a round bowl of the same size. Roughly 18% of the water is 15 ft or less, the band where the food chain lives. End to end it runs roughly 1.9 mi, about 0.3 mi across. It sits in Rainy River District. Its nearest charted neighbour, Pickwick Lake, is 2 mi to the north.
These fish are listed in an exact-water agency record as forage or ecological context. They are not target-species profiles and do not affect DepthScout's Prime, Good, or Fair spot ratings.
Official Ontario MNRF Fish ON-Line record. The listing documents source-recorded presence, not present abundance or guaranteed catchability.
Come spring, look for lake trout tight to the bank in 10 to 40 ft. Expect a summer slide to 23 to 78 ft, then a winter hold in 20 to 78 ft. Start at Deep basin. It's a deep basin holding about 70 ft of water and rates prime come summer. Prime time lands in early morning. A white tube jig (deep) or a magnum spoon on downrigger is the honest summer answer here.
Depth note: when a documented seasonal range extends below this chart, the table shows the deepest mapped working water, not a verified holding depth.
| Season | Depth | Best window | Start at | Go-to baits |
|---|---|---|---|---|
| Spring | 10 to 40 ft | dawn & dusk | Main-lake point (22 ft) | Casting spoon over shoals, Jerkbait (shallow) |
| Summer | 23 to 78 ft chart-limited; documented 50 to 120 ft | dawn | Deep basin (70 ft) | White tube jig (deep), Magnum spoon on downrigger |
| Fall | 10 to 50 ft | dusk & dawn | Main-lake point (22 ft) | Heavy casting spoon, Jigging rap over reefs |
| Winter | 20 to 78 ft chart-limited; documented 20 to 80 ft | dawn | Deep basin (70 ft) | White tube jig, Airplane jig |
The spring pattern is a shallow one: lake whitefish in 15 to 45 ft. As the season builds they drop to 23 to 78 ft, wintering in 25 to 70 ft. Top water on the chart: Deep basin, a deep basin in the 70 ft range, prime in summer. Time it for early morning. Summer baits: a blade bait vertical or a small jigging spoon gets it done.
Depth note: when a documented seasonal range extends below this chart, the table shows the deepest mapped working water, not a verified holding depth.
| Season | Depth | Best window | Start at | Go-to baits |
|---|---|---|---|---|
| Spring | 15 to 45 ft | midday & dawn | Back-bay flat (10 ft) | Small jig + waxworm, Blade bait (small) |
| Summer | 23 to 78 ft chart-limited; documented 40 to 90 ft | dawn | Deep basin (70 ft) | Blade bait vertical, Small jigging spoon |
| Fall | 8 to 30 ft | dusk | Main-lake point (22 ft) | Small spoon (gold), Jig + plastic larva |
| Winter | 25 to 70 ft | midday & dawn | Deep basin (70 ft) | Jigging spoon + bead chain, Tungsten jig + waxie |
Start shallow in spring: yellow perch sit in 3 to 12 ft that time of year. Warm water sends them out to 10 to 30 ft; cold water stacks them in 15 to 35 ft. Top water on the chart: Shallow bay flat, a feeding flat in the 8 ft range, prime in spring. Fish it in early morning and you'll meet the bite. Throw a drop-shot micro plastics or a small spoon tipped with worm until the fish tell you otherwise.
| Season | Depth | Best window | Start at | Go-to baits |
|---|---|---|---|---|
| Spring | 3 to 12 ft | midday & dawn | Shallow bay flat (8 ft) | Small jig + curly tail, Perch-pattern micro crank |
| Summer | 10 to 30 ft | dawn | Back-bay flat (10 ft) | Drop-shot micro plastics, Small spoon tipped with worm |
| Fall | 12 to 35 ft | midday | open water | Jigging spoon (small), Perch rig / spreader |
| Winter | 15 to 35 ft | midday & dawn | open water | Tungsten jig + spikes, Rattle spoon (small) |
Come spring, look for northern pike tight to the bank in 2 to 8 ft. They move out to 8 to 20 ft in summer and finish the year down in 5 to 15 ft. If you only fish one area, make it Shallow bay flat: a feeding flat around 8 ft that scores prime in spring. Best bite is early morning and the evening. A bucktail or a weedless spoon over cabbage is the honest summer answer here.
| Season | Depth | Best window | Start at | Go-to baits |
|---|---|---|---|---|
| Spring | 2 to 8 ft | midday & dawn | Shallow bay flat (8 ft) | #5 inline spinner, Spoon (red/white) |
| Summer | 8 to 20 ft | dawn & dusk | Shallow bay flat (8 ft) | Bucktail, Weedless spoon over cabbage |
| Fall | 6 to 18 ft | midday & dawn | Secondary point (9 ft) | Big rubber (Bull Dawg style), Husky-style jerkbait |
| Winter | 5 to 15 ft | midday | Shallow bay flat (8 ft) | Tip-ups, Large jigging spoon |
Come spring, look for burbot tight to the bank in 25 to 70 ft. Expect a summer slide to 23 to 78 ft, then a winter hold in 15 to 60 ft. Start at Deep basin. It's a deep basin holding about 70 ft of water and rates prime come spring. Prime time lands in after dark and midday. A heavy jig + cut bait is the honest summer answer here.
Depth note: when a documented seasonal range extends below this chart, the table shows the deepest mapped working water, not a verified holding depth.
| Season | Depth | Best window | Start at | Go-to baits |
|---|---|---|---|---|
| Spring | 25 to 70 ft | night & dusk | Deep basin (70 ft) | Glow jigging spoon + cut bait, Rattle bait (dark) |
| Summer | 23 to 78 ft chart-limited; documented 50 to 120 ft | night & midday | Deep basin (70 ft) | Heavy jig + cut bait |
| Fall | 23 to 78 ft chart-limited; documented 30 to 80 ft | night & dusk | Deep basin (70 ft) | Glow spoon + minnow head, Blade bait (slow) |
| Winter | 15 to 60 ft | night & dusk | Break off the point (57 ft) | Glow tungsten + cut bait, Rattle spoon + minnow head |
Count 6 structure marks on this chart. The deepest, Deep basin, sits near 70 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 Grimshaw Lake specifically, so confirm the current rules before you fish.
Check the official Ontario fishing regulations →
Grimshaw Lake is about 78 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, lake whitefish, yellow perch, northern pike, burbot on Grimshaw Lake.
Deep basin is the top-rated area: a deep basin in about 70 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 Grimshaw 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.
Pickwick Lake 2 mi · Weller Lake 3 mi · Tupman Lake 4 mi · Ryckman Lake 4 mi · Doman Lake 5 mi · Moose Lake 5 mi · Twist Lake 5 mi · Winkle Lake 5 mi · Hickerson Lake 5 mi · Big Sawbill Lake 6 mi · Strong Lake 6 mi · Cuttle Lake 6 mi
See how Grimshaw 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: Rainy River District fishing maps (257 charts). Browse all Ontario fishing maps. See every water on DepthScout. Bathymetry: published agency survey data. 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.