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4,076-acre lake in Thunder Bay District, Ontario. The lake tops out around 79 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 1974, a decades-old survey (a transect sounding survey). Here's the year, species by species, as the scoring engine sees it.
On the chart, Kopka River draws 4,092 acres inside 167.7 miles of shoreline, with 66 islands in the mix. A development index of 18.7 means a maze of bays and points: far more casting targets than a round bowl of the same size. 91% of the surface is littoral (under ~15 ft) — cover, weeds and forage water. Tip to tip the water measures near 50.5 mi with an 18.3-mi widest point. The water lies in Thunder Bay District. Closest neighbour on DepthScout: Awkward Lake, 6 mi west of here.
Spring puts lake trout in skinny water — 10 to 40 ft is the zone. As the season builds they drop to 24 to 79 ft, wintering in 20 to 79 ft. Fall lake trout concentrate at Rock reef, a prime-rated rock pile around 7 ft. Warm-month bites cluster around early morning. A white tube jig (deep) or a magnum spoon on downrigger 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 | 10 to 40 ft | dawn & dusk | Rock reef (7 ft) | Casting spoon over shoals, Jerkbait (shallow) |
| Summer | 24 to 79 ft chart-limited; documented 50 to 120 ft | dawn | open water | White tube jig (deep), Magnum spoon on downrigger |
| Fall | 10 to 50 ft | dusk & dawn | Rock reef (7 ft) | Heavy casting spoon, Jigging rap over reefs |
| Winter | 20 to 79 ft chart-limited; documented 20 to 80 ft | dawn | Rock reef (7 ft) | White tube jig, Airplane jig |
Early season lake whitefish use the shallows, holding in 15 to 45 ft. Expect a summer slide to 24 to 79 ft, then a winter hold in 25 to 70 ft. Put Rock reef first on the milk run — a rock pile near 7 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.
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 | 15 to 45 ft | midday & dawn | Shallow feeding flat (15 ft) | Small jig + waxworm, Blade bait (small) |
| Summer | 24 to 79 ft chart-limited; documented 40 to 90 ft | dawn | Shallow feeding flat (15 ft) | Blade bait vertical, Small jigging spoon |
| Fall | 8 to 30 ft | dusk | Rock reef (7 ft) | Small spoon (gold), Jig + plastic larva |
| Winter | 25 to 70 ft | midday & dawn | Shallow feeding flat (15 ft) | Jigging spoon + bead chain, Tungsten jig + waxie |
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 Rock reef: a rock pile around 5 ft that scores prime in spring. 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 (5 ft) | 1/8 oz jig + minnow, Hair jig |
| Summer | 15 to 35 ft | dusk & dawn | Shallow feeding flat (15 ft) | Crawler harness on bottom bouncer, Deep crankbait (trolled) |
| Fall | 12 to 40 ft | dusk & night | open water | Jigging rap, Jig + big minnow |
| Winter | 20 to 40 ft | dusk & dawn | open water | 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 feeding flat. It's a feeding flat holding about 15 ft of water and rates prime come summer. 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 feeding flat (15 ft) | Small jig + curly tail, Perch-pattern micro crank |
| Summer | 10 to 30 ft | dawn | Shallow feeding flat (15 ft) | Drop-shot micro plastics, Small spoon tipped with worm |
| Fall | 12 to 35 ft | midday | open water | Jigging spoon (small), Perch rig / spreader |
| Winter | 15 to 35 ft | midday & dawn | Shallow feeding flat (15 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 feeding flat, a feeding flat in about 15 ft of water that rates prime for northern pike in winter. 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 | open water | #5 inline spinner, Spoon (red/white) |
| Summer | 8 to 20 ft | dawn & dusk | Shallow feeding flat (15 ft) | Bucktail, Weedless spoon over cabbage |
| Fall | 6 to 18 ft | midday & dawn | Shallow feeding flat (15 ft) | Big rubber (Bull Dawg style), Husky-style jerkbait |
| Winter | 5 to 15 ft | midday | Shallow feeding flat (15 ft) | Tip-ups, Large jigging spoon |
Spring puts burbot in skinny water — 25 to 70 ft is the zone. As the season builds they drop to 24 to 79 ft, wintering in 15 to 60 ft. Winter burbot concentrate at Rock reef, a prime-rated rock pile around 7 ft. Warm-month bites cluster around after dark and midday. A heavy jig + cut bait 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 | 25 to 70 ft | night & dusk | Rock reef (7 ft) | Glow jigging spoon + cut bait, Rattle bait (dark) |
| Summer | 24 to 79 ft chart-limited; documented 50 to 120 ft | night & midday | open water | Heavy jig + cut bait |
| Fall | 24 to 79 ft chart-limited; documented 30 to 80 ft | night & dusk | Rock reef (7 ft) | Glow spoon + minnow head, Blade bait (slow) |
| Winter | 15 to 60 ft | night & dusk | Rock reef (7 ft) | Glow tungsten + cut bait, Rattle spoon + minnow head |
Kopka River carries 14 mapped structure features, topping out (or rather bottoming out) at Deep basin, about 70 ft down.
Access data: Geospatial Ontario - Fishing Access Points; Government of Ontario - MNR Unpatented Crown Land Shoreline; Government of Ontario - MNR Unpatented Crown Land Shoreline. Confirm conditions and fees locally before you launch.
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 Kopka River specifically, so confirm the current rules before you fish.
Check the official Ontario fishing regulations →
Kopka River is about 79 ft (24 m) deep at its deepest point. The depth data here comes from the Ontario MNRF survey of 1974, a decades-old survey (a transect sounding survey).
Anglers target lake trout, lake whitefish, walleye, yellow perch, northern pike, burbot on Kopka River. This isn't a survey of the lake — none is on record for it — but an informed estimate from the species Ontario's MNRF recorded in the nearest surveyed lakes, filtered to this lake's depth and habitat.
Rock reef is the top-rated area: a rock pile in about 7 ft of water that rates prime for lake whitefish in fall. Every other rated spot, per species and season, is on the map above.
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 Kopka River 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.
Awkward Lake 6 mi · North Whalen Lake 7 mi · Cooney Lake 8 mi · Maggotte Lake 9 mi · Vivid Lake 9 mi · Osemigwemowin Lake 10 mi · Kenakskaniss Lake 10 mi · Hornick Lake 10 mi · Obonga Lake 11 mi · Sandison Lake 11 mi · Crevasse Lake 12 mi · Uneven Lake 14 mi
See how Kopka River 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. 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.