Lake depth chart
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340-acre lake near Hubbard County. The lake tops out around 25 ft. The depth chart comes from Minnesota Department of Natural Resources bathymetric survey data, so the contours are survey-derived rather than computer-modeled. The depth data here comes from the Minnesota DNR survey of 1973, a decades-old survey (the DNR's original lake-survey map). The season-by-season read for each species follows, from the map's own numbers.
Drawn out, this is 340 acres of water rimmed by 4.9 miles of bank. Index 1.9 on the shoreline: a few honest points and pockets, nothing labyrinthine. About 50% of the surface sits shallower than 15 ft — that's the weed-and-bait zone. Call it 1.4 mi long by 0.6 mi wide at the broadest reach. You'll find it in Hubbard County. Closest neighbour on DepthScout: Round, 1 mi east of here.
Early season walleye use the shallows, holding in 4 to 15 ft. Expect a summer slide to 8 to 25 ft, then a winter hold in 8 to 25 ft. Put Break off the point first on the milk run — a drop-off near 25 ft that grades prime for fall. In summer the feeding windows fall in the evening and early morning. Tie on a crawler harness on bottom bouncer or a deep crankbait (trolled) 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 | 4 to 15 ft | dusk & dawn | Main-lake point (1 ft) | 1/8 oz jig + minnow, Hair jig |
| Summer | 8 to 25 ft chart-limited; documented 15 to 35 ft | dusk & dawn | Break off the point (25 ft) | Crawler harness on bottom bouncer, Deep crankbait (trolled) |
| Fall | 8 to 25 ft chart-limited; documented 12 to 40 ft | dusk & night | Break off the point (25 ft) | Jigging rap, Jig + big minnow |
| Winter | 8 to 25 ft chart-limited; documented 20 to 40 ft | dusk & dawn | Deep basin (25 ft) | Jigging spoon + minnow head, Rattle bait |
Spring yellow perch on Boulder hold shallow, usually 3 to 12 ft. They move out to 8 to 25 ft in summer and finish the year down in 8 to 25 ft. Put Deep basin first on the milk run — a deep basin near 25 ft that grades prime for fall. The feeding windows run early morning. The summer box starts with a drop-shot micro plastics or a small spoon tipped with worm.
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 | 3 to 12 ft | midday & dawn | Shallow bay flat (1 ft) | Small jig + curly tail, Perch-pattern micro crank |
| Summer | 8 to 25 ft chart-limited; documented 10 to 30 ft | dawn | Deep basin (25 ft) | Drop-shot micro plastics, Small spoon tipped with worm |
| Fall | 8 to 25 ft chart-limited; documented 12 to 35 ft | midday | Deep basin (25 ft) | Jigging spoon (small), Perch rig / spreader |
| Winter | 8 to 25 ft chart-limited; documented 15 to 35 ft | midday & dawn | Deep basin (25 ft) | Tungsten jig + spikes, Rattle spoon (small) |
Spring puts northern pike in skinny water — 2 to 8 ft is the zone. Warm water sends them out to 8 to 20 ft; cold water stacks them in 5 to 15 ft. Shallow bay flat is the standout, a weed flat at roughly 1 ft, rated prime for spring northern pike. Plan around early morning and the evening in the warm months. A bucktail or a weedless spoon over cabbage covers the summer program.
| Season | Depth | Best window | Start at | Go-to baits |
|---|---|---|---|---|
| Spring | 2 to 8 ft | midday & dawn | Shallow bay flat (1 ft) | #5 inline spinner, Spoon (red/white) |
| Summer | 8 to 20 ft | dawn & dusk | Break off the point (25 ft) | Bucktail, Weedless spoon over cabbage |
| Fall | 6 to 18 ft | midday & dawn | Shallow bay flat (1 ft) | Big rubber (Bull Dawg style), Husky-style jerkbait |
| Winter | 5 to 15 ft | midday | Shallow bay flat (1 ft) | Tip-ups, Large jigging spoon |
Spring puts smallmouth bass in skinny water — 3 to 12 ft is the zone. Warm water sends them out to 8 to 25 ft; cold water stacks them in 8 to 25 ft. Break off the point is the standout, a drop-off at roughly 25 ft, rated prime for winter smallmouth bass. Plan around early morning and the evening in the warm months. A drop shot (goby/minnow) or a ned rig 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 | 3 to 12 ft | dawn & dusk | Main-lake point (1 ft) | Ned rig, Tube jig |
| Summer | 8 to 25 ft chart-limited; documented 10 to 30 ft | dawn & dusk | Break off the point (25 ft) | Drop shot (goby/minnow), Ned rig |
| Fall | 8 to 25 ft | midday & dawn | Break off the point (25 ft) | Jerkbait, Blade bait |
| Winter | 8 to 25 ft chart-limited; documented 20 to 45 ft | midday | Break off the point (25 ft) | Blade bait, Hair jig |
In spring, largemouth bass run shallow here, mostly 2 to 10 ft. Midsummer fish sit out in 8 to 20 ft before dropping to 8 to 25 ft for winter. Winter largemouth bass concentrate at Break off the point, a prime-rated drop-off around 25 ft. Fish it in early morning and the evening and you'll meet the bite. You won't need more than a texas-rigged 10" worm or a deep-diving crankbait most summer days.
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 | 2 to 10 ft | dawn & dusk | Shallow bay flat (1 ft) | Spinnerbait, Chatterbait |
| Summer | 8 to 20 ft | dawn & dusk | Break off the point (25 ft) | Texas-rigged 10" worm, Deep-diving crankbait |
| Fall | 4 to 15 ft | midday & dawn | Main-lake point (1 ft) | Squarebill crankbait (shad), Spinnerbait |
| Winter | 8 to 25 ft chart-limited; documented 15 to 35 ft | midday | Break off the point (25 ft) | Blade bait, Jigging spoon |
When the water first warms, rock bass slide up into 2 to 10 ft. Summer is a 5 to 20 ft game here, winter an 8 to 25 ft one. Start at Deep basin. It's a deep basin holding about 25 ft of water and rates prime come winter. The feeding windows run the evening. Keep a ned rig (small) or a marabou jig rigged through the warm months.
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 | 2 to 10 ft | midday & dawn | Main-lake point (1 ft) | 1/16 oz jig + grub, Small inline spinner |
| Summer | 5 to 20 ft | dusk | Main-lake point (1 ft) | Ned rig (small), Marabou jig |
| Fall | 8 to 22 ft | midday | Break off the point (25 ft) | Small tube jig, Inline spinner |
| Winter | 8 to 25 ft chart-limited; documented 12 to 30 ft | midday | Deep basin (25 ft) | Tungsten jig + plastic, Small spoon + spike |
Boulder 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), black bullhead (3 to 15 ft in summer), yellow bullhead (3 to 15 ft in summer). Pick any of them on the map above for rated spots and bait picks.
The chart marks 6 structure features on Boulder; the deepest is Deep basin at about 25 ft.
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 |
|---|---|---|---|
| 2024* | Walleye (fingerlings) | 881 | — |
| 2024* | Walleye (yearlings) | 445 | — |
* Approximate date (agency reports month or season only). Source: Minnesota DNR LakeFinder stocking reports, retrieved 2026-09-23.
Season dates, license requirements, and size and bag limits for Minnesota waters are set by the Minnesota DNR — and special regulations can apply to Boulder specifically, so confirm the current rules before you fish.
Check the official Minnesota fishing regulations →
Boulder is about 25 ft (8 m) deep at its deepest point. The depth data here comes from the Minnesota DNR survey of 1973, a decades-old survey (the DNR's original lake-survey map).
Anglers target walleye, yellow perch, northern pike, smallmouth bass, largemouth bass, rock bass, crappie, bluegill, pumpkinseed, brown bullhead, black bullhead, yellow bullhead on Boulder.
Break off the point is the top-rated area: a drop-off in about 25 ft of water that rates prime for walleye in fall. The interactive chart above rates every 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.
Yes — per Minnesota DNR LakeFinder stocking reports records, Boulder was most recently stocked 2024 with 881 walleye (fingerlings). The full stocking history is listed above.
Fishing on Boulder 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.
Round 1 mi · Little Sand 2 mi · Ida 2 mi · Clausens 2 mi · Belle Taine 2 mi · Loon 2 mi · Shallow 2 mi · Gilmore 3 mi · Big Sand 3 mi · Deer 3 mi · Peysenske 3 mi · Emma 4 mi
See how Boulder 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: Hubbard County fishing maps (109 charts). Browse all Minnesota 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.