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Recent public catches load as you reach this section.
118-acre lake in Algoma District, Ontario. The lake tops out around 20 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 the Ontario MNRF survey of 1977, a decades-old survey (a transect sounding survey). Every species below gets its seasonal read from the same numbers driving the chart.
The drawn water covers 119 acres wrapped in 5.8 miles of bank. With a shoreline index of 3.8, this water is all arms and coves — edge habitat well beyond its acreage. Roughly 92% of the water is 15 ft or less, the band where the food chain lives. The basin spans about 2.2 mi end to end and 0.5 mi across at its widest. Algoma District claims this one. Crain Lake sits 3 mi northeast — the closest neighbouring chart.
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, brook trout slide up into 2 to 15 ft. Summer is a 6 to 20 ft game here, winter a 3 to 20 ft one. Start at Deep basin. It's a deep basin holding about 19 ft of water and rates prime come summer. The feeding windows run early morning and the evening. Keep a small spoon fished deep or a trolled lake-clear wobbler + 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 | 2 to 15 ft | dawn & dusk | Main-lake point (5 ft) | Small inline spinner (gold), Tiny spoon |
| Summer | 6 to 20 ft chart-limited; documented 10 to 30 ft | dawn & dusk | Deep basin (19 ft) | Small spoon fished deep, Trolled lake-clear wobbler + worm |
| Fall | 2 to 15 ft | midday & dawn | Main-lake point (5 ft) | Small spoon (orange), Spinner |
| Winter | 3 to 20 ft | dawn | Deep basin (19 ft) | Small jigging spoon, Tungsten jig + plastic |
Spring smallmouth bass on Flag Lake hold shallow, usually 3 to 12 ft. By summer they slide out to 6 to 20 ft, and by winter most fish are in 6 to 20 ft. The chart's best answer is Secondary point — point, 6 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.
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 | dawn & dusk | Main-lake point (5 ft) | Ned rig, Tube jig |
| Summer | 6 to 20 ft chart-limited; documented 10 to 30 ft | dawn & dusk | Break off the point (8 ft) | Drop shot (goby/minnow), Ned rig |
| Fall | 6 to 20 ft chart-limited; documented 8 to 25 ft | midday & dawn | Secondary point (6 ft) | Jerkbait, Blade bait |
| Winter | 6 to 20 ft chart-limited; documented 20 to 45 ft | midday | Break off the point (8 ft) | Blade bait, Hair jig |
Spring puts lake whitefish in skinny water — 6 to 20 ft is the zone. Summer fish stay in 6 to 20 ft, and winter fish hold in 6 to 20 ft. Deep basin is the standout, a deep basin at roughly 19 ft, rated prime for summer lake whitefish. Plan around early morning in the warm months. A blade bait vertical or a small jigging spoon 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 | 6 to 20 ft chart-limited; documented 15 to 45 ft | midday & dawn | Break off the point (8 ft) | Small jig + waxworm, Blade bait (small) |
| Summer | 6 to 20 ft chart-limited; documented 40 to 90 ft | dawn | Deep basin (19 ft) | Blade bait vertical, Small jigging spoon |
| Fall | 5 to 20 ft chart-limited; documented 8 to 30 ft | dusk | Break off the point (8 ft) | Small spoon (gold), Jig + plastic larva |
| Winter | 6 to 20 ft chart-limited; documented 25 to 70 ft | midday & dawn | Deep basin (19 ft) | Jigging spoon + bead chain, Tungsten jig + waxie |
Count 6 structure marks on this chart. The deepest, Deep basin, sits near 19 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 Flag Lake specifically, so confirm the current rules before you fish.
Check the official Ontario fishing regulations →
Flag Lake is about 20 ft (6 m) deep at its deepest point. The depth data here comes from the Ontario MNRF survey of 1977, a decades-old survey (a transect sounding survey).
Anglers target brook trout, smallmouth bass, lake whitefish on Flag Lake.
Secondary point is the top-rated area: a point in about 6 ft of water that rates prime for smallmouth bass in fall. Open the map above to see every rated spot for each 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 Flag 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.
Crain Lake 3 mi · Beyond Lake 3 mi · Finger Lake 3 mi · Salvage Lake 4 mi · Portelance L. 4 mi · Clara Lake 4 mi · Slender Lake 4 mi · Reed Lake 5 mi · Dolan Lake 5 mi · Kelsie Lake 5 mi · Pike Lake 5 mi · Oval Lake 5 mi
See how Flag Lake stacks up: best smallmouth bass lakes in Ontario · best brook trout lakes in Ontario · best lake whitefish lakes in Ontario
More water nearby: Algoma District fishing maps (1026 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.