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7,436-acre lake in Thunder Bay District, Ontario. The lake tops out around 154 ft. The chart is a model: real shoreline, published maximum depth, interpolated in between. A planning tool, never a navigation product. The season-by-season read for each species follows, from the map's own numbers.
Traced from the shoreline, Harmon Lake runs 7,469 acres with 118.6 miles of edge — 27 islands included. The 9.8 development index tells the story — a convoluted bank whose fishable edge far outruns the acreage. About 32% of the surface sits shallower than 15 ft on the modeled chart — that's the weed-and-bait zone. End to end it runs roughly 9.5 mi, about 7.5 mi across. The water lies in Thunder Bay District. For a second option, Rude Lake lies 7 mi southwest.
Spring puts lake trout in skinny water — 10 to 40 ft is the zone. As the season builds they drop to 50 to 120 ft, wintering in 20 to 80 ft. Winter lake trout concentrate at Offshore hump, a prime-rated offshore hump around 20 ft. Warm-month bites cluster around early morning. A white tube jig (deep) or a magnum spoon on downrigger covers the summer program.
| Season | Depth | Best window | Start at | Go-to baits |
|---|---|---|---|---|
| Spring | 10 to 40 ft | dawn & dusk | Main-lake point (39 ft) | Casting spoon over shoals, Jerkbait (shallow) |
| Summer | 50 to 120 ft | dawn | Deep basin (131 ft) | White tube jig (deep), Magnum spoon on downrigger |
| Fall | 10 to 50 ft | dusk & dawn | Rock reef (8 ft) | Heavy casting spoon, Jigging rap over reefs |
| Winter | 20 to 80 ft | dawn | Offshore hump (20 ft) | White tube jig, Airplane jig |
Early season lake whitefish use the shallows, holding in 15 to 45 ft. Expect a summer slide to 40 to 90 ft, then a winter hold in 25 to 70 ft. Put Rock reef first on the milk run — a rock pile near 8 ft that grades prime for fall. In summer the feeding windows fall in early morning. Tie on a blade bait vertical or a small jigging spoon and you're in the game.
| Season | Depth | Best window | Start at | Go-to baits |
|---|---|---|---|---|
| Spring | 15 to 45 ft | midday & dawn | Offshore hump (20 ft) | Small jig + waxworm, Blade bait (small) |
| Summer | 40 to 90 ft | dawn | Break off the point (69 ft) | Blade bait vertical, Small jigging spoon |
| Fall | 8 to 30 ft | dusk | Rock reef (8 ft) | Small spoon (gold), Jig + plastic larva |
| Winter | 25 to 70 ft | midday & dawn | Break off the point (69 ft) | Jigging spoon + bead chain, Tungsten jig + waxie |
Early season cisco (lake herring) use the shallows, holding in 10 to 40 ft. Expect a summer slide to 40 to 80 ft, then a winter hold in 20 to 60 ft. Put Offshore hump first on the milk run — an offshore hump near 20 ft that grades prime for winter. In summer the feeding windows fall in early morning. Tie on a vertical flutter spoon (small) or a drop-shot micro plastic and you're in the game.
| Season | Depth | Best window | Start at | Go-to baits |
|---|---|---|---|---|
| Spring | 10 to 40 ft | dawn & dusk | Offshore hump (20 ft) | Small silver spoon, Tiny swim jig (white) |
| Summer | 40 to 80 ft | dawn | Break off the point (69 ft) | Vertical flutter spoon (small), Drop-shot micro plastic |
| Fall | 5 to 25 ft | dusk & dawn | Rock reef (8 ft) | Small casting spoon, Inline spinner (silver) |
| Winter | 20 to 60 ft | dawn | Offshore hump (20 ft) | Small jigging spoon (glow/silver), Tungsten jig + minnow head |
Come spring, look for walleye tight to the bank in 4 to 15 ft. They move out to 15 to 35 ft in summer and finish the year down in 20 to 40 ft. If you only fish one area, make it Offshore hump: an offshore hump around 20 ft that scores prime in summer. Best bite is the evening and early morning. A crawler harness on bottom bouncer or a deep crankbait (trolled) is the honest summer answer here.
| Season | Depth | Best window | Start at | Go-to baits |
|---|---|---|---|---|
| Spring | 4 to 15 ft | dusk & dawn | Rock reef (8 ft) | 1/8 oz jig + minnow, Hair jig |
| Summer | 15 to 35 ft | dusk & dawn | Offshore hump (20 ft) | Crawler harness on bottom bouncer, Deep crankbait (trolled) |
| Fall | 12 to 40 ft | dusk & night | Sharp break (14 ft) | Jigging rap, Jig + big minnow |
| Winter | 20 to 40 ft | dusk & dawn | Offshore hump (20 ft) | Jigging spoon + minnow head, Rattle bait |
Come spring, look for yellow perch tight to the bank in 3 to 12 ft. Expect a summer slide to 10 to 30 ft, then a winter hold in 15 to 35 ft. Start at Shallow bay flat. It's a weed flat holding about 6 ft of water and rates prime come spring. Prime time lands in early morning. A drop-shot micro plastics or a small spoon tipped with worm is the honest summer answer here.
| Season | Depth | Best window | Start at | Go-to baits |
|---|---|---|---|---|
| Spring | 3 to 12 ft | midday & dawn | Shallow bay flat (6 ft) | Small jig + curly tail, Perch-pattern micro crank |
| Summer | 10 to 30 ft | dawn | Sharp break (14 ft) | Drop-shot micro plastics, Small spoon tipped with worm |
| Fall | 12 to 35 ft | midday | Sharp break (14 ft) | Jigging spoon (small), Perch rig / spreader |
| Winter | 15 to 35 ft | midday & dawn | Offshore hump (20 ft) | Tungsten jig + spikes, Rattle spoon (small) |
Start shallow in spring: northern pike sit in 2 to 8 ft that time of year. Summer pushes them deeper, 8 to 20 ft, and winter fish settle into 5 to 15 ft. The spot to know is Shallow bay flat, a weed flat in about 6 ft of water that rates prime for northern pike in spring. Warm-month bites cluster around early morning and the evening. Throw a bucktail or a weedless spoon over cabbage until the fish tell you otherwise.
| Season | Depth | Best window | Start at | Go-to baits |
|---|---|---|---|---|
| Spring | 2 to 8 ft | midday & dawn | Shallow bay flat (6 ft) | #5 inline spinner, Spoon (red/white) |
| Summer | 8 to 20 ft | dawn & dusk | Sharp break (14 ft) | Bucktail, Weedless spoon over cabbage |
| Fall | 6 to 18 ft | midday & dawn | Shallow bay flat (6 ft) | Big rubber (Bull Dawg style), Husky-style jerkbait |
| Winter | 5 to 15 ft | midday | Shallow bay flat (6 ft) | Tip-ups, Large jigging spoon |
Harmon Lake also holds rock bass (5 to 20 ft in summer), burbot (50 to 120 ft in summer). Pick any of them on the map above for rated spots and bait picks.
The chart marks 14 structure features on Harmon Lake; the deepest is Deep basin at about 131 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 Harmon Lake specifically, so confirm the current rules before you fish.
Check the official Ontario fishing regulations →
Harmon Lake is about 154 ft (47 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 lake trout, lake whitefish, cisco (lake herring), walleye, yellow perch, northern pike, rock bass, burbot on Harmon Lake.
Offshore hump is the top-rated area: an offshore hump in about 20 ft of water that rates prime for walleye in summer. Open the map above to see every rated spot for each 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 Harmon 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.
Rude Lake 7 mi · Grassy L. 7 mi · Wapikaimaski L. 8 mi · Sparkling Lake 10 mi · Waterhouse Lake 10 mi · Barbara L. 11 mi · Gaal Lake 12 mi · Antler L. 13 mi · Kashishibog Lake 14 mi · Uneven Lake 16 mi · Vanessa L. 16 mi · Empire Lake 16 mi
See how Harmon Lake stacks up: best walleye lakes in Ontario · best northern pike lakes in Ontario · best yellow perch lakes in Ontario · best lake trout lakes in Ontario
More water nearby: Thunder Bay District fishing maps (662 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.