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46-acre lake in Frontenac County, Ontario. The lake tops out around 72 ft. The depth data here comes from the Ontario MNRF survey of 1982 (a transect sounding survey). Here is how the season plays out for each species, straight from the data behind the map.
The outline encloses 46 acres, worked by 1.5 miles of shoreline. With a 1.6 development index there's bank structure worth casting at, in moderation. Roughly 15% of the water is 15 ft or less, the band where the food chain lives. End to end it runs roughly 0.6 mi, about 0.2 mi across. It sits in Frontenac County. If the bite dies, McCreary Lake is 3 mi to the east.
Come spring, look for lake trout tight to the bank in 10 to 40 ft. Expect a summer slide to 22 to 72 ft, then a winter hold in 18 to 72 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.
| Season | Depth | Best window | Start at | Go-to baits |
|---|---|---|---|---|
| Spring | 10 to 40 ft | dawn & dusk | Main-lake point (18 ft) | Casting spoon over shoals, Jerkbait (shallow) |
| Summer | 22 to 72 ft | dawn | Deep basin (70 ft) | White tube jig (deep), Magnum spoon on downrigger |
| Fall | 10 to 50 ft | dusk & dawn | Main-lake point (18 ft) | Heavy casting spoon, Jigging rap over reefs |
| Winter | 18 to 72 ft | dawn | Deep basin (70 ft) | White tube jig, Airplane jig |
When the water first warms, splake slide up into 5 to 25 ft. By summer they slide out to 25 to 60 ft, and by winter most fish are in 10 to 45 ft. If you only fish one area, make it Break off the point: a drop-off around 38 ft that scores prime in summer. In summer the feeding windows fall in early morning and the evening. Keep a trolled spoon at the thermocline or a white tube jig (deep) rigged through the warm months.
| Season | Depth | Best window | Start at | Go-to baits |
|---|---|---|---|---|
| Spring | 5 to 25 ft | dawn & dusk | Main-lake point (18 ft) | Small casting spoon (gold/orange), Inline spinner |
| Summer | 25 to 60 ft | dawn & dusk | Break off the point (38 ft) | Trolled spoon at the thermocline, White tube jig (deep) |
| Fall | 10 to 35 ft | dawn & dusk | Main-lake point (18 ft) | Casting spoon, Jerkbait |
| Winter | 10 to 45 ft | dawn | Break off the point (38 ft) | Jigging spoon tipped with minnow head, Small white tube |
Count 5 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 Big Mair Lake specifically, so confirm the current rules before you fish.
Check the official Ontario fishing regulations →
Big Mair Lake is about 72 ft (22 m) deep at its deepest point. The depth data here comes from the Ontario MNRF survey of 1982 (a transect sounding survey).
Anglers target lake trout, splake on Big Mair 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 Big Mair 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.
McCreary Lake 3 mi · Black Donald Lake 4 mi · Brue Lake 4 mi · Mousseau Lake 4 mi · Salmond Lake 4 mi · Round Schooner Lake 5 mi · Heifer Lake 5 mi · Scully Lake 5 mi · Leclaire Lake 5 mi · Steer Lake 5 mi · Wabun Lake 6 mi · Mair Lake 6 mi
See how Big Mair Lake stacks up: best lake trout lakes in Ontario · best splake lakes in Ontario
More water nearby: Frontenac County fishing maps (127 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.