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193-acre lake in Ontario. The lake tops out around 16 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 an MNRF lake survey by the Ontario MNRF. Here is how the season plays out for each species, straight from the data behind the map.
Traced from the shoreline, Lac St. Jean runs 194 acres with 3.4 miles of edge, broken up by an island. The shoreline is moderately structured (index 1.7) — enough points and pockets to pattern. All of it is shallow-zone water — under ~15 ft across the entire basin, so the food chain has the run of the place. Tip to tip the water measures near 1 mi with a 0.5-mi widest point. The water lies in Greater Sudbury / Grand Sudbury. The nearest mapped water is Ella Lake, 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.
When the water first warms, walleye slide up into 4 to 15 ft. Summer is a 5 to 16 ft game here, winter a 5 to 16 ft one. Start at Break off the point. It's a drop-off holding about 13 ft of water and rates prime come fall. The feeding windows run the evening and early morning. Keep a crawler harness on bottom bouncer or a deep crankbait (trolled) rigged through the warm months.
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 | 4 to 15 ft | dusk & dawn | Main-lake point (4 ft) | 1/8 oz jig + minnow, Hair jig |
| Summer | 5 to 16 ft chart-limited; documented 15 to 35 ft | dusk & dawn | Break off the point (13 ft) | Crawler harness on bottom bouncer, Deep crankbait (trolled) |
| Fall | 5 to 16 ft chart-limited; documented 12 to 40 ft | dusk & night | Break off the point (13 ft) | Jigging rap, Jig + big minnow |
| Winter | 5 to 16 ft chart-limited; documented 20 to 40 ft | dusk & dawn | Deep basin (15 ft) | Jigging spoon + minnow head, Rattle bait |
When the water first warms, yellow perch slide up into 3 to 12 ft. By summer they slide out to 5 to 16 ft, and by winter most fish are in 5 to 16 ft. If you only fish one area, make it Back-bay flat: a weed flat around 3 ft that scores prime in spring. In summer the feeding windows fall in early morning. Keep a drop-shot micro plastics or a small spoon tipped with worm rigged through the warm months.
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 | 3 to 12 ft | midday & dawn | Back-bay flat (3 ft) | Small jig + curly tail, Perch-pattern micro crank |
| Summer | 5 to 16 ft chart-limited; documented 10 to 30 ft | dawn | Deep basin (15 ft) | Drop-shot micro plastics, Small spoon tipped with worm |
| Fall | 5 to 16 ft chart-limited; documented 12 to 35 ft | midday | Deep basin (15 ft) | Jigging spoon (small), Perch rig / spreader |
| Winter | 5 to 16 ft chart-limited; documented 15 to 35 ft | midday & dawn | Deep basin (15 ft) | Tungsten jig + spikes, Rattle spoon (small) |
The spring pattern is a shallow one: northern pike in 2 to 8 ft. As the season builds they drop to 5 to 16 ft, wintering in 5 to 15 ft. Top water on the chart: Shallow bay flat, a weed flat in the 2 ft range, prime in spring. Time it for early morning and the evening. Summer baits: a bucktail or a weedless spoon over cabbage 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 | 2 to 8 ft | midday & dawn | Shallow bay flat (2 ft) | #5 inline spinner, Spoon (red/white) |
| Summer | 5 to 16 ft chart-limited; documented 8 to 20 ft | dawn & dusk | Break off the point (13 ft) | Bucktail, Weedless spoon over cabbage |
| Fall | 5 to 16 ft chart-limited; documented 6 to 18 ft | midday & dawn | Break off the point (13 ft) | Big rubber (Bull Dawg style), Husky-style jerkbait |
| Winter | 5 to 15 ft | midday | Back-bay flat (3 ft) | Tip-ups, Large jigging spoon |
Spring puts brown bullhead in skinny water — 2 to 8 ft is the zone. As the season builds they drop to 3 to 12 ft, wintering in 5 to 16 ft. Winter brown bullhead concentrate at Deep basin, a prime-rated deep basin around 15 ft. Warm-month bites cluster around after dark and the evening.
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 | 2 to 8 ft | dusk & night | Shallow bay flat (2 ft) | |
| Summer | 3 to 12 ft | night & dusk | Back-bay flat (3 ft) | |
| Fall | 5 to 15 ft | dusk | Deep basin (15 ft) | |
| Winter | 5 to 16 ft chart-limited; documented 10 to 25 ft | midday | Deep basin (15 ft) |
6 pieces of structure are mapped here — Deep basin, around 15 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 Lac St. Jean specifically, so confirm the current rules before you fish.
Check the official Ontario fishing regulations →
Lac St. Jean is about 16 ft (5 m) deep at its deepest point. The depth data here comes from an MNRF lake survey by the Ontario MNRF.
Anglers target walleye, yellow perch, northern pike, brown bullhead on Lac St. Jean.
Break off the point is the top-rated area: a drop-off in about 13 ft of water that rates prime for walleye in fall. The map above holds the full rated-spot list for every species and season.
For walleye, the summer bite is best in the evening and 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 Lac St. Jean 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.
Ella Lake 2 mi · Little Amy Lake 3 mi · Amy Lake 3 mi · Greens Lake 3 mi · Onwatin Lake 4 mi · Waddell Lake 5 mi · Selwyn Lake 6 mi · Lake Wanapitei 6 mi · Farm Lake 7 mi · Whitson Lake 9 mi · Tank Lake 9 mi · Joe Lake 9 mi
See how Lac St. Jean stacks up: best walleye lakes in Ontario · best northern pike lakes in Ontario · best yellow perch lakes in Ontario · best brown bullhead lakes in Ontario
More water nearby: Greater Sudbury / Grand Sudbury fishing maps (88 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.