Trio Lakes 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 Trio Lakes

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 Trio Lakes on the board.

Fishing Trio Lakes: what the data says

12-acre lake in Mineral County, Montana. The lake tops out around 70 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. Below is the species-by-species picture, pulled from the same data the map uses.

Drawn out, this is 12 acres of water rimmed by 0.5 miles of bank. At index 1 the outline is almost a bowl — read the depth changes, not the shoreline. The shallow band under 15 ft claims about 7% of the surface — that's where the groceries are. You'll find it in Mineral County. The nearest mapped water is Pearl Lake, 1 mi to the northwest.

Walleye fishing at Trio Lakes

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 Shallow bay flat: a feeding flat around 21 ft that scores good in summer. 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	open water	1/8 oz jig + minnow, Hair jig
Summer	15 to 35 ft	dusk & dawn	Shallow bay flat (21 ft)	Crawler harness on bottom bouncer, Deep crankbait (trolled)
Fall	12 to 40 ft	dusk & night	Shoreline break (57 ft)	Jigging rap, Jig + big minnow
Winter	20 to 40 ft	dusk & dawn	Deep basin (70 ft)	Jigging spoon + minnow head, Rattle bait

Northern Pike fishing at Trio Lakes

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 feeding flat in about 21 ft of water that rates prime for northern pike in summer. 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 (21 ft)	#5 inline spinner, Spoon (red/white)
Summer	8 to 20 ft	dawn & dusk	Shallow bay flat (21 ft)	Bucktail, Weedless spoon over cabbage
Fall	6 to 18 ft	midday & dawn	Shallow bay flat (21 ft)	Big rubber (Bull Dawg style), Husky-style jerkbait
Winter	5 to 15 ft	midday	Shallow bay flat (21 ft)	Tip-ups, Large jigging spoon

Yellow Perch fishing at Trio Lakes

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 feeding flat holding about 21 ft of water and rates prime come summer. 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 (21 ft)	Small jig + curly tail, Perch-pattern micro crank
Summer	10 to 30 ft	dawn	Shallow bay flat (21 ft)	Drop-shot micro plastics, Small spoon tipped with worm
Fall	12 to 35 ft	midday	Deep basin (70 ft)	Jigging spoon (small), Perch rig / spreader
Winter	15 to 35 ft	midday & dawn	Shallow bay flat (21 ft)	Tungsten jig + spikes, Rattle spoon (small)

Smallmouth Bass fishing at Trio Lakes

The spring pattern is a shallow one: smallmouth bass in 3 to 12 ft. Midsummer fish sit out in 10 to 30 ft before dropping to 20 to 45 ft for winter. The spot to know is Shoreline break, a drop-off in about 57 ft of water that rates good for smallmouth bass in winter. Plan around early morning and the evening in the warm months. Summer baits: a drop shot (goby/minnow) or a ned rig gets it done.

Season	Depth	Best window	Start at	Go-to baits
Spring	3 to 12 ft	dawn & dusk	open water	Ned rig, Tube jig
Summer	10 to 30 ft	dawn & dusk	Shoreline break (57 ft)	Drop shot (goby/minnow), Ned rig
Fall	8 to 25 ft	midday & dawn	Shoreline break (57 ft)	Jerkbait, Blade bait
Winter	20 to 45 ft	midday	Shoreline break (57 ft)	Blade bait, Hair jig

Rainbow Trout fishing at Trio Lakes

In spring, rainbow trout run shallow here, mostly 5 to 20 ft. Summer pushes them deeper, 8 to 30 ft, and winter fish settle into 8 to 40 ft. Shallow bay flat is the standout, a feeding flat at roughly 21 ft, rated good for summer rainbow trout. Time it for early morning and the evening. You won't need more than a dodger + spoon (deep troll) or a flutter spoon most summer days.

Season	Depth	Best window	Start at	Go-to baits
Spring	5 to 20 ft	dawn & dusk	Shallow bay flat (21 ft)	Inline spinner (silver), Small spoon
Summer	8 to 30 ft	dawn & dusk	Shallow bay flat (21 ft)	Dodger + spoon (deep troll), Flutter spoon
Fall	10 to 35 ft	dawn & dusk	open water	Casting spoon, Jerkbait over shoals
Winter	8 to 40 ft	dawn	Shoreline break (57 ft)	Jigging spoon, Tube jig (white)

Lake Trout fishing at Trio Lakes

In spring, lake trout run shallow here, mostly 10 to 40 ft. Midsummer fish sit out in 21 to 70 ft before dropping to 18 to 70 ft for winter. Summer lake trout concentrate at Deep basin, a prime-rated deep basin around 70 ft. Fish it in early morning and you'll meet the bite. You won't need more than a white tube jig (deep) or a magnum spoon on downrigger most summer days.

Season	Depth	Best window	Start at	Go-to baits
Spring	10 to 40 ft	dawn & dusk	open water	Casting spoon over shoals, Jerkbait (shallow)
Summer	21 to 70 ft	dawn	Deep basin (70 ft)	White tube jig (deep), Magnum spoon on downrigger
Fall	10 to 50 ft	dusk & dawn	Shoreline break (57 ft)	Heavy casting spoon, Jigging rap over reefs
Winter	18 to 70 ft	dawn	Deep basin (70 ft)	White tube jig, Airplane jig

Trio Lakes 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

Structure-wise the chart holds 3 features, led in depth by Deep basin at roughly 70 ft.

Deep basin: deep basin, around 70 ft
Shoreline break: drop-off, around 57 ft
Shallow bay flat: feeding flat, around 21 ft

Trio Lakes 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 Trio Lakes specifically, so confirm the current rules before you fish.

Check the official Montana fishing regulations →

Common questions

How deep is Trio Lakes?

Trio Lakes is about 70 ft (21 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 Trio Lakes?

Anglers target walleye, northern pike, yellow perch, smallmouth bass, rainbow trout, lake trout, crappie, channel catfish on Trio Lakes. 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 Trio Lakes?

Deep basin is the top-rated area: a deep basin in about 70 ft of water that rates prime for lake trout in summer. The map above holds the full rated-spot list for every species and season.

When is the best time to fish Trio Lakes?

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 Trio Lakes?

Fishing on Trio Lakes 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

Pearl Lake 1 mi · Hidden Lake (Mineral) 2 mi · French Lake 2 mi · Crater Lake 3 mi · Hoodoo Lake 4 mi · Siamese Lake, Upper 6 mi · Siamese Lake, Lower 6 mi · Cedar Log Lake, North 11 mi · Oregon Lake, Middle 11 mi · Surveyor Lake 12 mi · Cedar Log Lake, South 12 mi · Bonanza Lake, Upper 14 mi

See how Trio Lakes 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: Mineral County fishing maps (19 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.