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209-acre lake in Nipissing 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. What the data behind the map says about each species, season by season:
The drawn water covers 209 acres wrapped in 3.6 miles of bank. With a 1.8 development index there's bank structure worth casting at, in moderation. The basin spans about 1.1 mi end to end and 0.5 mi across at its widest. Nipissing District claims this one. If the bite dies, Sargesson Lake is 1 mi to the west.
Spring puts walleye in skinny water — 4 to 15 ft is the zone. As the season builds they drop to 6 to 20 ft, wintering in 6 to 20 ft. Winter walleye concentrate at Deep basin, a prime-rated deep basin around 13 ft. Warm-month bites cluster around the evening and early morning. A crawler harness on bottom bouncer or a deep crankbait (trolled) covers the summer program.
| Season | Depth | Best window | Start at | Go-to baits |
|---|---|---|---|---|
| Spring | 4 to 15 ft | dusk & dawn | Main-lake point (2 ft) | 1/8 oz jig + minnow, Hair jig |
| Summer | 6 to 20 ft | dusk & dawn | Deep basin (13 ft) | Crawler harness on bottom bouncer, Deep crankbait (trolled) |
| Fall | 6 to 20 ft | dusk & night | Deep basin (13 ft) | Jigging rap, Jig + big minnow |
| Winter | 6 to 20 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. Summer pushes them deeper, 6 to 20 ft, and winter fish settle into 6 to 20 ft. The spot to know is Back-bay flat, a weed flat in about 3 ft of water that rates prime for yellow perch in spring. Warm-month bites cluster around early morning. Throw a drop-shot micro plastics or a small spoon tipped with worm until the fish tell you otherwise.
| 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 | 6 to 20 ft | dawn | Deep basin (13 ft) | Drop-shot micro plastics, Small spoon tipped with worm |
| Fall | 6 to 20 ft | midday | Deep basin (13 ft) | Jigging spoon (small), Perch rig / spreader |
| Winter | 6 to 20 ft | midday & dawn | Deep basin (13 ft) | Tungsten jig + spikes, Rattle spoon (small) |
Start shallow in spring: striped bass sit in 5 to 20 ft that time of year. They don't go far with the seasons — 6 to 20 ft covers summer, 6 to 20 ft covers winter. The spot to know is Deep basin, a deep basin in about 13 ft of water that rates prime for striped bass in summer. Warm-month bites cluster around early morning and the evening. Throw a topwater walker at low light or a paddletail on a light jig until the fish tell you otherwise.
| Season | Depth | Best window | Start at | Go-to baits |
|---|---|---|---|---|
| Spring | 5 to 20 ft | dawn & dusk | Main-lake point (2 ft) | 3-5 inch baitfish swimbait, Suspending minnow plug |
| Summer | 6 to 20 ft | dawn & dusk | Deep basin (13 ft) | Topwater walker at low light, Paddletail on a light jig |
| Fall | 6 to 20 ft | dawn & dusk | Deep basin (13 ft) | Baitfish swimbait, Metal jig |
| Winter | 6 to 20 ft | midday | Deep basin (13 ft) | Slow paddletail, Bucktail near bottom |
Theriault Lake carries 6 mapped structure features, topping out (or rather bottoming out) at Deep basin, about 13 ft down.
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 Theriault Lake specifically, so confirm the current rules before you fish.
Check the official Ontario fishing regulations →
Theriault Lake is about 20 ft (6 m) deep at its deepest point. 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.
Anglers target walleye, yellow perch, striped bass on Theriault Lake.
Deep basin is the top-rated area: a deep basin in about 13 ft of water that rates prime for walleye in winter. Scroll up to the map for the complete spot list by 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 Theriault 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.
Sargesson Lake 1 mi · Pine Lake 3 mi · Jake Lake 4 mi · Dwyer Lake 5 mi · Murray Lake 6 mi · Silver Lake 6 mi · Apple Lake 7 mi · McNish Lake 8 mi · Tee Lake 8 mi · Washagami Lake 8 mi · Deschamps Lake 8 mi · Weever Lake 8 mi
See how Theriault Lake stacks up: best walleye lakes in Ontario · best yellow perch lakes in Ontario
More water nearby: Nipissing District fishing maps (683 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.