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64-acre lake near St. Louis County. The lake tops out around 51 ft. The contours come from a model of the real basin shape and its known max depth. Read them as probabilities, not soundings, and keep them out of navigation decisions. The rest of this page walks each species through its year, using the map's own scoring.
On the chart, Boulder draws 64 acres inside 2.6 miles of shoreline, broken up by an island. That shoreline is heavily fingered (development index 2.4) — bays, points and pockets everywhere, which multiplies the fishable edge. About 48% of the surface sits shallower than 15 ft on the modeled chart — that's the weed-and-bait zone. Call it 0.6 mi long by 0.4 mi wide at the broadest reach. You'll find it in St. Louis County. For a second option, Phantom lies 1 mi east.
When the water first warms, walleye slide up into 4 to 15 ft. By summer they slide out to 15 to 35 ft, and by winter most fish are in 20 to 40 ft. If you only fish one area, make it Break off the point: a drop-off around 23 ft that scores prime in fall. In summer the feeding windows fall in the evening and early morning. Keep a crawler harness on bottom bouncer or a deep crankbait (trolled) rigged through the warm months.
| Season | Depth | Best window | Start at | Go-to baits |
|---|---|---|---|---|
| Spring | 4 to 15 ft | dusk & dawn | Main-lake point (13 ft) | 1/8 oz jig + minnow, Hair jig |
| Summer | 15 to 35 ft | dusk & dawn | Break off the point (23 ft) | Crawler harness on bottom bouncer, Deep crankbait (trolled) |
| Fall | 12 to 40 ft | dusk & night | Break off the point (23 ft) | Jigging rap, Jig + big minnow |
| Winter | 20 to 40 ft | dusk & dawn | Deep basin (43 ft) | Jigging spoon + minnow head, Rattle bait |
When the water first warms, yellow perch slide up into 3 to 12 ft. Summer is a 10 to 30 ft game here, winter a 15 to 35 ft one. Start at Shallow bay flat. It's a weed flat holding about 6 ft of water and rates prime come spring. The feeding windows run early morning. Keep a drop-shot micro plastics or a small spoon tipped with worm rigged through the warm months.
| 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 | Break off the point (23 ft) | Drop-shot micro plastics, Small spoon tipped with worm |
| Fall | 12 to 35 ft | midday | Break off the point (23 ft) | Jigging spoon (small), Perch rig / spreader |
| Winter | 15 to 35 ft | midday & dawn | Break off the point (23 ft) | Tungsten jig + spikes, Rattle spoon (small) |
The spring pattern is a shallow one: northern pike in 2 to 8 ft. Midsummer fish sit out in 8 to 20 ft before dropping to 5 to 15 ft for winter. 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. Plan around early morning and the evening in the warm months. Summer baits: a bucktail or a weedless spoon over cabbage gets it done.
| 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 | Shallow bay flat (6 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 |
Start shallow in spring: largemouth bass sit in 2 to 10 ft that time of year. Warm water sends them out to 8 to 20 ft; cold water stacks them in 15 to 35 ft. Top water on the chart: Shallow bay flat, a weed flat in the 6 ft range, prime in spring. Fish it in early morning and the evening and you'll meet the bite. Throw a texas-rigged 10" worm or a deep-diving crankbait until the fish tell you otherwise.
| Season | Depth | Best window | Start at | Go-to baits |
|---|---|---|---|---|
| Spring | 2 to 10 ft | dawn & dusk | Shallow bay flat (6 ft) | Spinnerbait, Chatterbait |
| Summer | 8 to 20 ft | dawn & dusk | Main-lake point (13 ft) | Texas-rigged 10" worm, Deep-diving crankbait |
| Fall | 4 to 15 ft | midday & dawn | Main-lake point (13 ft) | Squarebill crankbait (shad), Spinnerbait |
| Winter | 15 to 35 ft | midday | Break off the point (23 ft) | Blade bait, Jigging spoon |
Spring puts bluegill in skinny water — 1 to 6 ft is the zone. Warm water sends them out to 4 to 15 ft; cold water stacks them in 10 to 25 ft. Shallow bay flat is the standout, a weed flat at roughly 6 ft, rated prime for spring bluegill. Plan around early morning and the evening in the warm months. A small sponge spider (fly) or a micro tube jig covers the summer program.
| Season | Depth | Best window | Start at | Go-to baits |
|---|---|---|---|---|
| Spring | 1 to 6 ft | midday & dusk | Shallow bay flat (6 ft) | 1/32 oz jig + micro plastic, Tiny popper (evenings) |
| Summer | 4 to 15 ft | dawn & dusk | Shallow bay flat (6 ft) | Small sponge spider (fly), Micro tube jig |
| Fall | 6 to 18 ft | midday | Shallow bay flat (6 ft) | Micro jig + waxworm, Small spoon tipped |
| Winter | 10 to 25 ft | midday | Break off the point (23 ft) | Tungsten ice jig + plastic, Tiny spoon |
The chart marks 6 structure features on Boulder; the deepest is Deep basin at about 43 ft.
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 51 ft (16 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 walleye, yellow perch, northern pike, largemouth bass, bluegill on Boulder.
Break off the point is the top-rated area: a drop-off in about 23 ft of water that rates prime for walleye in fall. Scroll up to the map for the complete spot list by 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 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.
Phantom 1 mi · Battle 1 mi · Sprite 1 mi · Meat 2 mi · Hassel 2 mi · Glimmer 2 mi · Schlamm 2 mi · Saca 2 mi · Clark 2 mi · Tamarack 2 mi · Lunetta 3 mi · Mud 3 mi
See how Boulder stacks up: best largemouth bass lakes in Minnesota · best walleye lakes in Minnesota · best northern pike lakes in Minnesota · best bluegill lakes in Minnesota
More water nearby: St. Louis County fishing maps (429 charts). Browse all Minnesota 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.