Boulder Lake Depth Map & Fishing Spots (MT)

Hatch outlook

Grasshoppers (east-side summer)Active window

Typical here: Jul 1 – Oct 15 · until the hard frosts of mid-October; on the Missouri, August hoppers fish mid-river, not the banks

adultall day in high summer, best when afternoon wind knocks bugs onto the water

Pulls fish to the windward grassy banks and edges for months — fish the bank the wind blows ONTO.

The friendliest crossover of the summer: on lakes, drift the windward bank with a bubble-and-foam-hopper — the bubble's splash doesn't hurt a hopper presentation. On rivers, the same rig dead-drifted along the undercut grass banks, or small gold spinners under the banks between rises.

The event happens over grassy banks, undercut edges and windward shorelines

Spruce MothActive window

Typical here: Jul 20 – Aug 31 · a conifer-forest event — it needs fir and lodgepole on the banks, so it's a Rock Creek / Blackfoot / upper Bitterroot specialty

adultmorning through midday — moths don't enter the water willingly — landings are sporadic and near the conifer banks; fish the imitation LOW in the film with minimal floatant, even fully drowned, with a little movement

When the moths show, just about every run produces — large trout key on them so hard that one pattern carries the whole box for two weeks.

Honest limit: a small drowned-surface moth has no lure analog. The workable rig is a casting bubble with a drowned moth pattern along the timbered banks in the morning; otherwise fish spinners early and late and leave the moth window to the film.

2–3 weeks at best, and day-to-day — fish key on the moths when they show and vanish with them

The event happens over banks under conifers — the moths rarely reach mid-river

Recommendations come from depth structure and seasonal species behavior. Treat them as a starting point, not a guarantee. Contours here are interpolated from real agency depth surveys (state DNR / USACE). Never use for navigation. Always check local regulations.

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Recent catches at Boulder Lake

Shared by DepthScout anglers. Exact spots stay private, always.

No shared catches here yet — be the first.Log a catch from the map above and share it to put Boulder Lake on the board.

Fishing Boulder Lake: what the data says

95-acre lake in Missoula County, Montana. The lake tops out around 90 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. Here is how the season plays out for each species, straight from the data behind the map.

Drawn out, this is 109 acres of water rimmed by 1.7 miles of bank. The basin is a simple one (shoreline index 1.2) — close to a bowl, so the structure on the chart matters more than the bank. 20% of the surface is littoral (under ~15 ft) — cover, weeds and forage water. The basin spans about 0.6 mi end to end and 0.4 mi across at its widest. You'll find it in Missoula County. Closest neighbour on DepthScout: Fly Lake (Missoula), 1 mi northeast of here.

Walleye fishing at Boulder Lake

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 Secondary point. It's a point holding about 13 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	Main-lake point (11 ft)	1/8 oz jig + minnow, Hair jig
Summer	15 to 35 ft	dusk & dawn	Secondary point (13 ft)	Crawler harness on bottom bouncer, Deep crankbait (trolled)
Fall	12 to 40 ft	dusk & night	Secondary point (13 ft)	Jigging rap, Jig + big minnow
Winter	20 to 40 ft	dusk & dawn	Deep basin (86 ft)	Jigging spoon + minnow head, Rattle bait

Northern Pike fishing at Boulder Lake

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: Shallow bay flat, a feeding flat in the 5 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	Shallow bay flat (5 ft)	#5 inline spinner, Spoon (red/white)
Summer	8 to 20 ft	dawn & dusk	Main-lake point (11 ft)	Bucktail, Weedless spoon over cabbage
Fall	6 to 18 ft	midday & dawn	Main-lake point (11 ft)	Big rubber (Bull Dawg style), Husky-style jerkbait
Winter	5 to 15 ft	midday	Shallow bay flat (5 ft)	Tip-ups, Large jigging spoon

Yellow Perch fishing at Boulder Lake

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 5 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 (5 ft)	Small jig + curly tail, Perch-pattern micro crank
Summer	10 to 30 ft	dawn	Back-bay flat (6 ft)	Drop-shot micro plastics, Small spoon tipped with worm
Fall	12 to 35 ft	midday	Deep basin (86 ft)	Jigging spoon (small), Perch rig / spreader
Winter	15 to 35 ft	midday & dawn	Deep basin (86 ft)	Tungsten jig + spikes, Rattle spoon (small)

Smallmouth Bass fishing at Boulder Lake

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 11 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	Main-lake point (11 ft)	Ned rig, Tube jig
Summer	10 to 30 ft	dawn & dusk	Main-lake point (11 ft)	Drop shot (goby/minnow), Ned rig
Fall	8 to 25 ft	midday & dawn	Main-lake point (11 ft)	Jerkbait, Blade bait
Winter	20 to 45 ft	midday	Break off the point (56 ft)	Blade bait, Hair jig

Rainbow Trout fishing at Boulder Lake

Spring puts rainbow trout in skinny water — 5 to 20 ft is the zone. As the season builds they drop to 8 to 30 ft, wintering in 8 to 40 ft. Spring rainbow trout concentrate at Main-lake point, a prime-rated point around 11 ft. Warm-month bites cluster around early morning and the evening. A dodger + spoon (deep troll) or a flutter spoon covers the summer program.

Season	Depth	Best window	Start at	Go-to baits
Spring	5 to 20 ft	dawn & dusk	Main-lake point (11 ft)	Inline spinner (silver), Small spoon
Summer	8 to 30 ft	dawn & dusk	Main-lake point (11 ft)	Dodger + spoon (deep troll), Flutter spoon
Fall	10 to 35 ft	dawn & dusk	Main-lake point (11 ft)	Casting spoon, Jerkbait over shoals
Winter	8 to 40 ft	dawn	Break off the point (56 ft)	Jigging spoon, Tube jig (white)

Lake Trout fishing at Boulder Lake

Spring puts lake trout in skinny water — 10 to 40 ft is the zone. Warm water sends them out to 27 to 90 ft; cold water stacks them in 20 to 80 ft. Deep basin is the standout, a deep basin at roughly 86 ft, rated prime for summer lake trout. Plan around early morning in the warm months. A white tube jig (deep) or a magnum spoon on downrigger covers the summer program.

Season	Depth	Best window	Start at	Go-to baits
Spring	10 to 40 ft	dawn & dusk	Main-lake point (11 ft)	Casting spoon over shoals, Jerkbait (shallow)
Summer	27 to 90 ft	dawn	Deep basin (86 ft)	White tube jig (deep), Magnum spoon on downrigger
Fall	10 to 50 ft	dusk & dawn	Main-lake point (11 ft)	Heavy casting spoon, Jigging rap over reefs
Winter	20 to 80 ft	dawn	Deep basin (86 ft)	White tube jig, Airplane jig

Boulder Lake also holds crappie (10 to 25 ft in summer), channel catfish (8 to 25 ft in summer). Pick any of them on the map above for rated spots and bait picks.

Notable structure

Count 6 structure marks on this chart. The deepest, Deep basin, sits near 86 ft.

Deep basin: deep basin, around 86 ft
Break off the point: drop-off, around 56 ft
Secondary point: point, around 13 ft
Main-lake point: point, around 11 ft
Back-bay flat: feeding flat, around 6 ft
Shallow bay flat: feeding flat, around 5 ft

Boulder Lake fishing regulations

Season dates, license requirements, and size and bag limits for Montana waters are set by the Montana Fish, Wildlife & Parks — and special regulations can apply to Boulder Lake specifically, so confirm the current rules before you fish.

Check the official Montana fishing regulations →

Common questions

How deep is Boulder Lake?

Boulder Lake is about 90 ft (27 m) deep at its deepest point. The depth chart here comes from real state fisheries GPS surveys, so the contours reflect measured depths.

What fish are in Boulder Lake?

Anglers target walleye, northern pike, yellow perch, smallmouth bass, rainbow trout, lake trout, crappie, channel catfish on Boulder Lake. This isn't a survey of the water — none is published for it — but an informed estimate from the species common to the region, narrowed by this water's depth, size and each species' range.

Where is the best fishing spot on Boulder Lake?

Main-lake point is the top-rated area: a point in about 11 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.

When is the best time to fish Boulder Lake?

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.

What are the fishing regulations for Boulder Lake?

Fishing on Boulder Lake is regulated by the Montana Fish, Wildlife & Parks. Check the official Montana regulations for current license requirements, season dates, and size and bag limits — special regulations can apply to this specific water.

Nearby waters

Fly Lake (Missoula) 1 mi · Rattlesnake Lake #22 4 mi · Sheridan Lake 4 mi · Little Lake 5 mi · Big Lake 5 mi · Sanders Lake 5 mi · Glacier Lake 5 mi · Farmers Lake #6 6 mi · McKinley Lake 6 mi · Farmers Lake #5 6 mi · Lake Elsina 13 mi · St Marys Lake 14 mi

See how Boulder Lake stacks up: best smallmouth bass lakes in Montana · best walleye lakes in Montana · best northern pike lakes in Montana · best crappie lakes in Montana

More water nearby: Missoula County fishing maps (37 charts). Browse all Montana 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.