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1,347-acre lake near Cass County. The lake tops out around 80 ft. The depth data here comes from the Minnesota DNR survey of 1937, a decades-old survey (the DNR's original lake-survey map). Here is how the season plays out for each species, straight from the data behind the map.
The drawn water covers 1,347 acres wrapped in 15.4 miles of bank. With a shoreline index of 3, this water is all arms and coves — edge habitat well beyond its acreage. Roughly 20% of the water is 15 ft or less, the band where the food chain lives. Call it 3 mi long by 2 mi wide at the broadest reach. It sits in Cass County. Kidney sits 2 mi south — the closest neighbouring chart.
The spring pattern is a shallow one: cisco (lake herring) in 10 to 40 ft. As the season builds they drop to 40 to 80 ft, wintering in 20 to 60 ft. Top water on the chart: Deep basin, a deep basin in the 79 ft range, prime in summer. Time it for early morning. Summer baits: a vertical flutter spoon (small) or a drop-shot micro plastic gets it done.
| Season | Depth | Best window | Start at | Go-to baits |
|---|---|---|---|---|
| Spring | 10 to 40 ft | dawn & dusk | Break off the point (28 ft) | Small silver spoon, Tiny swim jig (white) |
| Summer | 40 to 80 ft | dawn | Deep basin (79 ft) | Vertical flutter spoon (small), Drop-shot micro plastic |
| Fall | 5 to 25 ft | dusk & dawn | Break off the point (28 ft) | Small casting spoon, Inline spinner (silver) |
| Winter | 20 to 60 ft | dawn | Break off the point (28 ft) | Small jigging spoon (glow/silver), Tungsten jig + minnow head |
Spring puts walleye in skinny water — 4 to 15 ft is the zone. Warm water sends them out to 15 to 35 ft; cold water stacks them in 20 to 40 ft. Break off the point is the standout, a drop-off at roughly 28 ft, rated prime for fall walleye. Plan around the evening and early morning in the warm months. 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 (8 ft) | 1/8 oz jig + minnow, Hair jig |
| Summer | 15 to 35 ft | dusk & dawn | Break off the point (28 ft) | Crawler harness on bottom bouncer, Deep crankbait (trolled) |
| Fall | 12 to 40 ft | dusk & night | Break off the point (28 ft) | Jigging rap, Jig + big minnow |
| Winter | 20 to 40 ft | dusk & dawn | Break off the point (28 ft) | Jigging spoon + minnow head, Rattle bait |
Start shallow in spring: yellow perch 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 15 to 35 ft. Top water on the chart: Shallow bay flat, a weed flat in the 8 ft range, prime in spring. Fish it in early morning and you'll meet the bite. 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 | Shallow bay flat (8 ft) | Small jig + curly tail, Perch-pattern micro crank |
| Summer | 10 to 30 ft | dawn | Break off the point (28 ft) | Drop-shot micro plastics, Small spoon tipped with worm |
| Fall | 12 to 35 ft | midday | Break off the point (28 ft) | Jigging spoon (small), Perch rig / spreader |
| Winter | 15 to 35 ft | midday & dawn | Break off the point (28 ft) | Tungsten jig + spikes, Rattle spoon (small) |
Come spring, look for northern pike tight to the bank in 2 to 8 ft. They move out to 8 to 20 ft in summer and finish the year down in 5 to 15 ft. If you only fish one area, make it Shallow bay flat: a weed flat around 8 ft that scores prime in spring. Best bite is early morning and the evening. A bucktail or a weedless spoon over cabbage is the honest summer answer here.
| Season | Depth | Best window | Start at | Go-to baits |
|---|---|---|---|---|
| Spring | 2 to 8 ft | midday & dawn | Shallow bay flat (8 ft) | #5 inline spinner, Spoon (red/white) |
| Summer | 8 to 20 ft | dawn & dusk | Shallow bay flat (8 ft) | Bucktail, Weedless spoon over cabbage |
| Fall | 6 to 18 ft | midday & dawn | Shallow bay flat (8 ft) | Big rubber (Bull Dawg style), Husky-style jerkbait |
| Winter | 5 to 15 ft | midday | Shallow bay flat (8 ft) | Tip-ups, Large jigging spoon |
Come spring, look for smallmouth bass 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 20 to 45 ft. If you only fish one area, make it Main-lake point: a point around 8 ft that scores prime in fall. Best bite is early morning and the evening. A drop shot (goby/minnow) or a ned rig is the honest summer answer here.
| Season | Depth | Best window | Start at | Go-to baits |
|---|---|---|---|---|
| Spring | 3 to 12 ft | dawn & dusk | Main-lake point (8 ft) | Ned rig, Tube jig |
| Summer | 10 to 30 ft | dawn & dusk | Break off the point (28 ft) | Drop shot (goby/minnow), Ned rig |
| Fall | 8 to 25 ft | midday & dawn | Main-lake point (8 ft) | Jerkbait, Blade bait |
| Winter | 20 to 45 ft | midday | Break off the point (28 ft) | Blade bait, Hair jig |
When the water first warms, largemouth bass slide up into 2 to 10 ft. Summer is an 8 to 20 ft game here, winter a 15 to 35 ft one. Start at Shallow bay flat. It's a weed flat holding about 8 ft of water and rates prime come spring. The feeding windows run early morning and the evening. Keep a texas-rigged 10" worm or a deep-diving crankbait rigged through the warm months.
| Season | Depth | Best window | Start at | Go-to baits |
|---|---|---|---|---|
| Spring | 2 to 10 ft | dawn & dusk | Shallow bay flat (8 ft) | Spinnerbait, Chatterbait |
| Summer | 8 to 20 ft | dawn & dusk | Shallow bay flat (8 ft) | Texas-rigged 10" worm, Deep-diving crankbait |
| Fall | 4 to 15 ft | midday & dawn | Main-lake point (8 ft) | Squarebill crankbait (shad), Spinnerbait |
| Winter | 15 to 35 ft | midday | Break off the point (28 ft) | Blade bait, Jigging spoon |
Thunder also holds rock bass (5 to 20 ft in summer), 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), burbot (24 to 80 ft in summer). Pick any of them on the map above for rated spots and bait picks.
7 pieces of structure are mapped here — Deep basin, around 79 ft, is the deepest of them.
Access data: MN DNR Water Access Sites (struc_water_access_sites), Minnesota Geospatial Commons. Confirm conditions and fees locally before you launch.
| Date | Species | Count | Size |
|---|---|---|---|
| 2025* | Walleye (fingerlings) | 11,752 | — |
* Approximate date (agency reports month or season only). Source: Minnesota DNR LakeFinder stocking reports, retrieved 2026-08-18.
Season dates, license requirements, and size and bag limits for Minnesota waters are set by the Minnesota DNR — and special regulations can apply to Thunder specifically, so confirm the current rules before you fish.
Check the official Minnesota fishing regulations →
Thunder is about 80 ft (24 m) deep at its deepest point. The depth data here comes from the Minnesota DNR survey of 1937, a decades-old survey (the DNR's original lake-survey map).
Anglers target cisco (lake herring), walleye, yellow perch, northern pike, smallmouth bass, largemouth bass, rock bass, crappie, bluegill, pumpkinseed, brown bullhead, burbot on Thunder.
Deep basin is the top-rated area: a deep basin in about 79 ft of water that rates prime for cisco (lake herring) in summer. Open the map above to see every rated spot for each species and season.
For cisco (lake herring), 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.
Yes — per Minnesota DNR LakeFinder stocking reports records, Thunder was most recently stocked 2025 with 11,752 walleye (fingerlings). The full stocking history is listed above.
Fishing on Thunder 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.
Kidney 2 mi · Little Thunder 2 mi · Little Bass 2 mi · Bass 3 mi · Laura 3 mi · Island 3 mi · Upper Trelipe 3 mi · Big Rice 4 mi · Michaud 4 mi · Mitten 4 mi · Twenty-Six 5 mi · Little Thunder (West Bay) 5 mi
See how Thunder 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.