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535-acre lake near Cass County. The lake tops out around 100 ft. The depth chart is built from real state fisheries GPS surveys, so the humps, channels and drop-offs you see are measured, not guessed. What the data behind the map says about each species, season by season:
Traced from the shoreline, Big Deep runs 535 acres with 5 miles of edge. The shoreline is moderately structured (index 1.5) — enough points and pockets to pattern. About 11% of the surface sits shallower than 15 ft — that's the weed-and-bait zone. Tip to tip the water measures near 2.1 mi with a 0.7-mi widest point. You'll find it in Cass County. For a second option, Trillium lies 2 mi north.
Come spring, look for walleye tight to the bank in 4 to 15 ft. Expect a summer slide to 15 to 35 ft, then a winter hold in 20 to 40 ft. Start at Main-lake point. It's a point holding about 18 ft of water and rates prime come fall. Prime time lands in 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 | Secondary point (7 ft) | 1/8 oz jig + minnow, Hair jig |
| Summer | 15 to 35 ft | dusk & dawn | Main-lake point (18 ft) | Crawler harness on bottom bouncer, Deep crankbait (trolled) |
| Fall | 12 to 40 ft | dusk & night | Main-lake point (18 ft) | Jigging rap, Jig + big minnow |
| Winter | 20 to 40 ft | dusk & dawn | Main-lake point (18 ft) | Jigging spoon + minnow head, Rattle bait |
Come spring, look for yellow perch tight to the bank in 3 to 12 ft. They move out to 10 to 30 ft in summer and finish the year down in 15 to 35 ft. If you only fish one area, make it Shallow bay flat: a feeding flat around 11 ft that scores prime in spring. Best bite is 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 (11 ft) | Small jig + curly tail, Perch-pattern micro crank |
| Summer | 10 to 30 ft | dawn | Shallow bay flat (11 ft) | Drop-shot micro plastics, Small spoon tipped with worm |
| Fall | 12 to 35 ft | midday | Deep basin (100 ft) | Jigging spoon (small), Perch rig / spreader |
| Winter | 15 to 35 ft | midday & dawn | Deep basin (100 ft) | Tungsten jig + spikes, Rattle spoon (small) |
Start shallow in spring: northern pike sit in 2 to 8 ft that time of year. Warm water sends them out to 8 to 20 ft; cold water stacks them in 5 to 15 ft. Top water on the chart: Back-bay flat, a feeding flat in the 4 ft range, prime in spring. Fish it in early morning and the evening and you'll meet the bite. 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 | Back-bay flat (4 ft) | #5 inline spinner, Spoon (red/white) |
| Summer | 8 to 20 ft | dawn & dusk | Shallow bay flat (11 ft) | Bucktail, Weedless spoon over cabbage |
| Fall | 6 to 18 ft | midday & dawn | Main-lake point (18 ft) | Big rubber (Bull Dawg style), Husky-style jerkbait |
| Winter | 5 to 15 ft | midday | Shallow bay flat (11 ft) | Tip-ups, Large jigging spoon |
Start shallow in spring: smallmouth bass sit in 3 to 12 ft that time of year. Warm water sends them out to 10 to 30 ft; cold water stacks them in 20 to 45 ft. Top water on the chart: Main-lake point, a point in the 18 ft range, prime in fall. Fish it in early morning and the evening and you'll meet the bite. Throw a drop shot (goby/minnow) or a ned rig until the fish tell you otherwise.
| Season | Depth | Best window | Start at | Go-to baits |
|---|---|---|---|---|
| Spring | 3 to 12 ft | dawn & dusk | Secondary point (7 ft) | Ned rig, Tube jig |
| Summer | 10 to 30 ft | dawn & dusk | Main-lake point (18 ft) | Drop shot (goby/minnow), Ned rig |
| Fall | 8 to 25 ft | midday & dawn | Main-lake point (18 ft) | Jerkbait, Blade bait |
| Winter | 20 to 45 ft | midday | Break off the point (95 ft) | Blade bait, Hair jig |
The spring pattern is a shallow one: largemouth bass in 2 to 10 ft. Midsummer fish sit out in 8 to 20 ft before dropping to 15 to 35 ft for winter. The spot to know is Secondary point, a point in about 7 ft of water that rates prime for largemouth bass in fall. Plan around early morning and the evening in the warm months. Summer baits: a texas-rigged 10" worm or a deep-diving crankbait gets it done.
| Season | Depth | Best window | Start at | Go-to baits |
|---|---|---|---|---|
| Spring | 2 to 10 ft | dawn & dusk | Back-bay flat (4 ft) | Spinnerbait, Chatterbait |
| Summer | 8 to 20 ft | dawn & dusk | Main-lake point (18 ft) | Texas-rigged 10" worm, Deep-diving crankbait |
| Fall | 4 to 15 ft | midday & dawn | Secondary point (7 ft) | Squarebill crankbait (shad), Spinnerbait |
| Winter | 15 to 35 ft | midday | Break off the point (95 ft) | Blade bait, Jigging spoon |
Early season rock bass use the shallows, holding in 2 to 10 ft. Summer is a 5 to 20 ft game here, winter a 12 to 30 ft one. The chart's best answer is Main-lake point — point, 18 ft, prime for summer. Best bite is the evening. Tie on a ned rig (small) or a marabou jig and you're in the game.
| Season | Depth | Best window | Start at | Go-to baits |
|---|---|---|---|---|
| Spring | 2 to 10 ft | midday & dawn | Secondary point (7 ft) | 1/16 oz jig + grub, Small inline spinner |
| Summer | 5 to 20 ft | dusk | Main-lake point (18 ft) | Ned rig (small), Marabou jig |
| Fall | 8 to 22 ft | midday | Main-lake point (18 ft) | Small tube jig, Inline spinner |
| Winter | 12 to 30 ft | midday | Deep basin (100 ft) | Tungsten jig + plastic, Small spoon + spike |
Big Deep also holds crappie (10 to 25 ft in summer), bluegill (4 to 15 ft in summer), pumpkinseed (2 to 10 ft in summer), brown bullhead (3 to 12 ft in summer). Pick any of them on the map above for rated spots and bait picks.
Big Deep carries 6 mapped structure features, topping out (or rather bottoming out) at Deep basin, about 100 ft down.
Season dates, license requirements, and size and bag limits for Minnesota waters are set by the Minnesota DNR — and special regulations can apply to Big Deep specifically, so confirm the current rules before you fish.
Check the official Minnesota fishing regulations →
Big Deep is about 100 ft (30 m) deep at its deepest point. The depth chart here comes from real state fisheries GPS surveys, so the contours reflect measured depths.
Anglers target walleye, yellow perch, northern pike, smallmouth bass, largemouth bass, rock bass, crappie, bluegill, pumpkinseed, brown bullhead on Big Deep.
Main-lake point is the top-rated area: a point in about 18 ft of water that rates prime for smallmouth bass in fall. Open the map above to see every rated spot for each 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 Big Deep is regulated by the Minnesota DNR. Check the official Minnesota regulations for current license requirements, season dates, and size and bag limits — special regulations can apply to this specific water.
Trillium 2 mi · Long 2 mi · Sand 2 mi · Kerr 2 mi · Lost 2 mi · Widow 3 mi · Deep Portage 3 mi · Kid 3 mi · Island 3 mi · Squeedunk 3 mi · IXL 3 mi · Child 3 mi
See how Big Deep stacks up: best largemouth bass lakes in Minnesota · best smallmouth bass lakes in Minnesota · best walleye lakes in Minnesota · best northern pike lakes in Minnesota
More water nearby: Cass County fishing maps (217 charts). Browse all Minnesota 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.