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Shared by DepthScout anglers. Exact spots stay private, always.
17-acre lake in Cochrane District, Ontario. The lake tops out around 64 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 1975, a decades-old survey (an MNRF lake survey). What follows comes from the same scoring engine that paints the spots above.
The outline encloses 16 acres, worked by 0.7 miles of shoreline. Its 1.3 shoreline index means few bank features; the contours below do the pattern work. 85% of the surface is littoral (under ~15 ft) — cover, weeds and forage water. Figure 0.3 mi of water from one end to the other. Cochrane District claims this one. Its nearest charted neighbour, Jefferson Lake, is 0 mi to the northwest.
In spring, yellow perch run shallow here, mostly 3 to 12 ft. Summer pushes them deeper, 10 to 30 ft, and winter fish settle into 15 to 35 ft. Shallow bay flat is the standout, a weed flat at roughly 2 ft, rated prime for spring yellow perch. Time it for early morning. You won't need more than a drop-shot micro plastics or a small spoon tipped with worm most summer days.
| Season | Depth | Best window | Start at | Go-to baits |
|---|---|---|---|---|
| Spring | 3 to 12 ft | midday & dawn | Shallow bay flat (2 ft) | Small jig + curly tail, Perch-pattern micro crank |
| Summer | 10 to 30 ft | dawn | Shoreline break (9 ft) | Drop-shot micro plastics, Small spoon tipped with worm |
| Fall | 12 to 35 ft | midday | Shoreline break (9 ft) | Jigging spoon (small), Perch rig / spreader |
| Winter | 15 to 35 ft | midday & dawn | Deep basin (45 ft) | Tungsten jig + spikes, Rattle spoon (small) |
Early season northern pike use the shallows, holding in 2 to 8 ft. Expect a summer slide to 8 to 20 ft, then a winter hold in 5 to 15 ft. Put Shallow bay flat first on the milk run — a weed flat near 2 ft that grades prime for spring. In summer the feeding windows fall in early morning and the evening. Tie on a bucktail or a weedless spoon over cabbage and you're in the game.
| 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 | 8 to 20 ft | dawn & dusk | Shoreline break (9 ft) | Bucktail, Weedless spoon over cabbage |
| Fall | 6 to 18 ft | midday & dawn | Shoreline break (9 ft) | Big rubber (Bull Dawg style), Husky-style jerkbait |
| Winter | 5 to 15 ft | midday | Shallow bay flat (2 ft) | Tip-ups, Large jigging spoon |
4 pieces of structure are mapped here — Deep basin, around 45 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 Big Jefferson L. specifically, so confirm the current rules before you fish.
Check the official Ontario fishing regulations →
Big Jefferson L. is about 64 ft (20 m) deep at its deepest point. The depth data here comes from the Ontario MNRF survey of 1975, a decades-old survey (an MNRF lake survey).
Anglers target yellow perch, northern pike on Big Jefferson L..
Shallow bay flat is the top-rated area: a weed flat in about 2 ft of water that rates prime for northern pike in spring. The interactive chart above rates every spot for each species and season.
For yellow perch, 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 Jefferson L. 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.
Jefferson Lake 0 mi · Portelance L. 0 mi · Pool Lake 2 mi · Fletchers Lake 2 mi · Little Lake 2 mi · Menard Lake 5 mi · Little Menard Lake 5 mi · Mann L. 2 6 mi · Mann L. 3 6 mi · Mann L. 4 6 mi · L. 12F-12 6 mi · L. 12F-6 6 mi
See how Big Jefferson L. stacks up: best northern pike lakes in Ontario · best yellow perch lakes in Ontario
More water nearby: Cochrane District fishing maps (673 charts). Browse all Ontario fishing maps or 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.