Lake Marshall 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 Lake Marshall

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 Lake Marshall on the board.

Fishing Lake Marshall: what the data says

82-acre lake in Missoula County, Montana. The lake tops out around 56 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.

The drawn water covers 82 acres wrapped in 1.7 miles of bank. The basin is a simple one (shoreline index 1.3) — close to a bowl, so the structure on the chart matters more than the bank. The shallow band under 15 ft claims about 15% of the surface — that's where the groceries are. Tip to tip the water measures near 0.8 mi with a 0.2-mi widest point. Missoula County claims this one. Its nearest charted neighbour, Lake Alva, is 4 mi to the northeast.

Brook Trout fishing at Lake Marshall

Come spring, look for brook trout tight to the bank in 2 to 15 ft. They move out to 10 to 30 ft in summer and finish the year down in 3 to 20 ft. If you only fish one area, make it Main-lake point: a point around 11 ft that scores prime in spring. Best bite is early morning and the evening. A small spoon fished deep or a trolled lake-clear wobbler + worm is the honest summer answer here.

Season	Depth	Best window	Start at	Go-to baits
Spring	2 to 15 ft	dawn & dusk	Main-lake point (11 ft)	Small inline spinner (gold), Tiny spoon
Summer	10 to 30 ft	dawn & dusk	open water	Small spoon fished deep, Trolled lake-clear wobbler + worm
Fall	2 to 15 ft	midday & dawn	Main-lake point (11 ft)	Small spoon (orange), Spinner
Winter	3 to 20 ft	dawn	Shallow bay flat (7 ft)	Small jigging spoon, Tungsten jig + plastic

Lake Whitefish fishing at Lake Marshall

In spring, lake whitefish run shallow here, mostly 15 to 45 ft. Midsummer fish sit out in 17 to 56 ft before dropping to 17 to 56 ft for winter. Summer lake whitefish concentrate at Deep basin, a prime-rated deep basin around 56 ft. Fish it in early morning and you'll meet the bite. You won't need more than a blade bait vertical or a small jigging spoon most summer days.

Season	Depth	Best window	Start at	Go-to baits
Spring	15 to 45 ft	midday & dawn	Break off the point (52 ft)	Small jig + waxworm, Blade bait (small)
Summer	17 to 56 ft	dawn	Deep basin (56 ft)	Blade bait vertical, Small jigging spoon
Fall	8 to 30 ft	dusk	Main-lake point (11 ft)	Small spoon (gold), Jig + plastic larva
Winter	17 to 56 ft	midday & dawn	Deep basin (56 ft)	Jigging spoon + bead chain, Tungsten jig + waxie

Cutthroat Trout fishing at Lake Marshall

The spring pattern is a shallow one: cutthroat trout in 3 to 15 ft. As the season builds they drop to 10 to 35 ft, wintering in 10 to 40 ft. Top water on the chart: Main-lake point, a point in the 11 ft range, prime in fall. Time it for early morning and the evening. Summer baits: a trolled spoon (small) or an inline spinner gets it done.

Season	Depth	Best window	Start at	Go-to baits
Spring	3 to 15 ft	dawn & dusk	Main-lake point (11 ft)	Inline spinner (silver/gold), Small spoon
Summer	10 to 35 ft	dawn & dusk	Main-lake point (11 ft)	Trolled spoon (small), Inline spinner
Fall	5 to 25 ft	dawn & dusk	Main-lake point (11 ft)	Casting spoon, Inline spinner
Winter	10 to 40 ft	dawn	Main-lake point (11 ft)	Small jigging spoon, Marabou jig

Rainbow Trout fishing at Lake Marshall

When the water first warms, rainbow trout slide up into 5 to 20 ft. Summer is an 8 to 30 ft game here, winter an 8 to 40 ft one. Start at Main-lake point. It's a point holding about 11 ft of water and rates prime come spring. The feeding windows run early morning and the evening. Keep a dodger + spoon (deep troll) or a flutter spoon rigged through the warm months.

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 (52 ft)	Jigging spoon, Tube jig (white)

Notable structure

The chart marks 5 structure features on Lake Marshall; the deepest is Deep basin at about 56 ft.

Deep basin: deep basin, around 56 ft
Break off the point: drop-off, around 52 ft
Main-lake point: point, around 11 ft
Shallow bay flat: feeding flat, around 7 ft
Secondary point: point, around 4 ft

Lake Marshall 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 Lake Marshall specifically, so confirm the current rules before you fish.

Check the official Montana fishing regulations →

Common questions

How deep is Lake Marshall?

Lake Marshall is about 56 ft (17 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 Lake Marshall?

Anglers target brook trout, lake whitefish, cutthroat trout, rainbow trout on Lake Marshall.

Where is the best fishing spot on Lake Marshall?

Deep basin is the top-rated area: a deep basin in about 56 ft of water that rates prime for lake whitefish in summer. Scroll up to the map for the complete spot list by species and season.

When is the best time to fish Lake Marshall?

For brook trout, the summer bite is best in early morning and the evening. 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 Lake Marshall?

Fishing on Lake Marshall 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

Lake Alva 4 mi · Lake Elsina 4 mi · Lake Inez 4 mi · Rainy Lake 4 mi · Colt Lake 5 mi · Summit Lake (Missoula) 6 mi · South Meadow Lake 7 mi · Lindbergh Lake 7 mi · Pierce Lake 7 mi · Clearwater Lake 8 mi · Morrell Lake 9 mi · Seeley Lake 9 mi

See how Lake Marshall stacks up: best rainbow trout lakes in Montana · best brook trout lakes in Montana · best lake whitefish lakes in Montana · best cutthroat trout 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.