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Recent public catches load as you reach this section.
162-acre lake in Kenora District, Ontario. The lake tops out around 15 ft. Depth here is modeled from the true shoreline and max depth rather than surveyed; use it to plan, not to navigate. The rest of this page walks each species through its year, using the map's own scoring.
The outline encloses 161 acres, worked by 3 miles of shoreline. With a 1.7 development index there's bank structure worth casting at, in moderation. The basin spans about 0.9 mi end to end and 0.6 mi across at its widest. It sits in Kenora District. Square Lake sits 1 mi east — the closest neighbouring chart.
Spring puts walleye in skinny water — 4 to 15 ft is the zone. Summer fish stay in 5 to 15 ft, and winter fish hold in 5 to 15 ft. Break off the point is the standout, a drop-off at roughly 7 ft, rated prime for fall walleye. Plan around the evening and early morning in the warm months. A crawler harness on bottom bouncer or a deep crankbait (trolled) covers the summer program.
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 (8 ft) | 1/8 oz jig + minnow, Hair jig |
| Summer | 5 to 15 ft chart-limited; documented 15 to 35 ft | dusk & dawn | Break off the point (7 ft) | Crawler harness on bottom bouncer, Deep crankbait (trolled) |
| Fall | 5 to 15 ft chart-limited; documented 12 to 40 ft | dusk & night | Break off the point (7 ft) | Jigging rap, Jig + big minnow |
| Winter | 5 to 15 ft chart-limited; documented 20 to 40 ft | dusk & dawn | Deep basin (13 ft) | Jigging spoon + minnow head, Rattle bait |
Start shallow in spring: yellow perch sit in 3 to 12 ft that time of year. Warm water sends them out to 5 to 15 ft; cold water stacks them in 5 to 15 ft. Top water on the chart: Shallow bay flat, a weed flat in the 3 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.
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 | Shallow bay flat (3 ft) | Small jig + curly tail, Perch-pattern micro crank |
| Summer | 5 to 15 ft chart-limited; documented 10 to 30 ft | dawn | Deep basin (13 ft) | Drop-shot micro plastics, Small spoon tipped with worm |
| Fall | 5 to 15 ft chart-limited; documented 12 to 35 ft | midday | Deep basin (13 ft) | Jigging spoon (small), Perch rig / spreader |
| Winter | 5 to 15 ft chart-limited; documented 15 to 35 ft | midday & dawn | Deep basin (13 ft) | 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 5 to 15 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 weed flat around 3 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.
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 (3 ft) | #5 inline spinner, Spoon (red/white) |
| Summer | 5 to 15 ft chart-limited; documented 8 to 20 ft | dawn & dusk | Break off the point (7 ft) | Bucktail, Weedless spoon over cabbage |
| Fall | 5 to 15 ft chart-limited; documented 6 to 18 ft | midday & dawn | Break off the point (7 ft) | Big rubber (Bull Dawg style), Husky-style jerkbait |
| Winter | 5 to 15 ft | midday | Shallow bay flat (3 ft) | Tip-ups, Large jigging spoon |
Structure-wise the chart holds 6 features, led in depth by Deep basin at roughly 13 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 Ostrum Lake specifically, so confirm the current rules before you fish.
Check the official Ontario fishing regulations →
Ostrum Lake is about 15 ft (5 m) deep at its deepest point. The contours here are modeled from the water's real shape and maximum depth, so treat them as a rough guide.
Anglers target walleye, yellow perch, northern pike on Ostrum Lake.
Break off the point is the top-rated area: a drop-off in about 7 ft of water that rates prime for walleye in fall. The interactive chart above rates every spot for each 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 Ostrum 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.
Square Lake 1 mi · Dollar Lake 3 mi · Godden Lake 4 mi · Gustauson Lake 4 mi · Arethusa Lake 4 mi · Abamategwia Lake 4 mi · Reguly Lake 4 mi · Snowstorm Lake 5 mi · Little Snowstorm Lake 5 mi · Widow Lake 6 mi · Heathwalt Lake 6 mi · Steinhoff Lake 6 mi
See how Ostrum Lake stacks up: best walleye lakes in Ontario · best northern pike lakes in Ontario · best yellow perch lakes in Ontario
More water nearby: Kenora District fishing maps (1173 charts). Browse all Ontario fishing maps. See every water on DepthScout. 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.