Blue Lake (Flathead) 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.

Loading depth chart…

Recent catches at Blue Lake (Flathead)

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 Blue Lake (Flathead) on the board.

Fishing Blue Lake (Flathead): what the data says

12-acre lake in Flathead 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. The season-by-season read for each species follows, from the map's own numbers.

Blue Lake (Flathead) maps at 15 acres behind 0.7 miles of shoreline. A shoreline index of 1.3 says round and simple: fish relate to depth changes here, not shoreline features. Littoral water — the productive band under ~15 ft — makes up 13% of this chart. Tip to tip the water measures near 0.3 mi. Flathead County claims this one. Fish Lake (Lincoln) sits 2 mi northeast — the closest neighbouring chart.

Walleye fishing at Blue Lake (Flathead)

In spring, walleye run shallow here, mostly 4 to 15 ft. Summer pushes them deeper, 15 to 35 ft, and winter fish settle into 20 to 40 ft. Shoreline break is the standout, a drop-off at roughly 23 ft, rated prime for fall walleye. Time it for the evening and early morning. You won't need more than a crawler harness on bottom bouncer or a deep crankbait (trolled) most summer days.

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	Shoreline break (23 ft)	Crawler harness on bottom bouncer, Deep crankbait (trolled)
Fall	12 to 40 ft	dusk & night	Shoreline break (23 ft)	Jigging rap, Jig + big minnow
Winter	20 to 40 ft	dusk & dawn	Shoreline break (23 ft)	Jigging spoon + minnow head, Rattle bait

Northern Pike fishing at Blue Lake (Flathead)

When the water first warms, northern pike slide up into 2 to 8 ft. By summer they slide out to 8 to 20 ft, and by winter most fish are in 5 to 15 ft. If you only fish one area, make it Shallow bay flat: a feeding flat around 7 ft that scores prime in spring. In summer the feeding windows fall in early morning and the evening. Keep a bucktail or a weedless spoon over cabbage rigged through the warm months.

Season	Depth	Best window	Start at	Go-to baits
Spring	2 to 8 ft	midday & dawn	Shallow bay flat (7 ft)	#5 inline spinner, Spoon (red/white)
Summer	8 to 20 ft	dawn & dusk	Back-bay flat (16 ft)	Bucktail, Weedless spoon over cabbage
Fall	6 to 18 ft	midday & dawn	Shallow bay flat (7 ft)	Big rubber (Bull Dawg style), Husky-style jerkbait
Winter	5 to 15 ft	midday	Shallow bay flat (7 ft)	Tip-ups, Large jigging spoon

Yellow Perch fishing at Blue Lake (Flathead)

The spring pattern is a shallow one: yellow perch in 3 to 12 ft. As the season builds they drop to 10 to 30 ft, wintering in 15 to 35 ft. Top water on the chart: Shoreline break, a drop-off in the 23 ft range, prime in summer. Time it for early morning. Summer baits: a drop-shot micro plastics or a small spoon tipped with worm gets it done.

Season	Depth	Best window	Start at	Go-to baits
Spring	3 to 12 ft	midday & dawn	Shallow bay flat (7 ft)	Small jig + curly tail, Perch-pattern micro crank
Summer	10 to 30 ft	dawn	Shoreline break (23 ft)	Drop-shot micro plastics, Small spoon tipped with worm
Fall	12 to 35 ft	midday	Shoreline break (23 ft)	Jigging spoon (small), Perch rig / spreader
Winter	15 to 35 ft	midday & dawn	Shoreline break (23 ft)	Tungsten jig + spikes, Rattle spoon (small)

Smallmouth Bass fishing at Blue Lake (Flathead)

When the water first warms, smallmouth bass slide up into 3 to 12 ft. By summer they slide out to 10 to 30 ft, and by winter most fish are in 20 to 45 ft. If you only fish one area, make it Shoreline break: a drop-off around 23 ft that scores prime in winter. In summer the feeding windows fall in early morning and the evening. Keep a drop shot (goby/minnow) or a ned rig rigged through the warm months.

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 (23 ft)	Drop shot (goby/minnow), Ned rig
Fall	8 to 25 ft	midday & dawn	Shoreline break (23 ft)	Jerkbait, Blade bait
Winter	20 to 45 ft	midday	Shoreline break (23 ft)	Blade bait, Hair jig

Rainbow Trout fishing at Blue Lake (Flathead)

Spring rainbow trout on Blue Lake (Flathead) hold shallow, usually 5 to 20 ft. They move out to 8 to 30 ft in summer and finish the year down in 8 to 40 ft. Put Shoreline break first on the milk run — a drop-off near 23 ft that grades prime for winter. The feeding windows run early morning and the evening. The summer box starts with a dodger + spoon (deep troll) or a flutter spoon.

Season	Depth	Best window	Start at	Go-to baits
Spring	5 to 20 ft	dawn & dusk	Shallow bay flat (7 ft)	Inline spinner (silver), Small spoon
Summer	8 to 30 ft	dawn & dusk	Shoreline break (23 ft)	Dodger + spoon (deep troll), Flutter spoon
Fall	10 to 35 ft	dawn & dusk	Shoreline break (23 ft)	Casting spoon, Jerkbait over shoals
Winter	8 to 40 ft	dawn	Shoreline break (23 ft)	Jigging spoon, Tube jig (white)

Lake Trout fishing at Blue Lake (Flathead)

When the water first warms, lake trout slide up into 10 to 40 ft. Summer is a 21 to 70 ft game here, winter an 18 to 70 ft one. Start at Deep basin. It's a deep basin holding about 69 ft of water and rates prime come summer. The feeding windows run early morning. Keep a white tube jig (deep) or a magnum spoon on downrigger rigged through the warm months.

Season	Depth	Best window	Start at	Go-to baits
Spring	10 to 40 ft	dawn & dusk	Shoreline break (23 ft)	Casting spoon over shoals, Jerkbait (shallow)
Summer	21 to 70 ft	dawn	Deep basin (69 ft)	White tube jig (deep), Magnum spoon on downrigger
Fall	10 to 50 ft	dusk & dawn	Shoreline break (23 ft)	Heavy casting spoon, Jigging rap over reefs
Winter	18 to 70 ft	dawn	Deep basin (69 ft)	White tube jig, Airplane jig

Blue Lake (Flathead) 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 4 features, led in depth by Deep basin at roughly 69 ft.

Deep basin: deep basin, around 69 ft
Shoreline break: drop-off, around 23 ft
Back-bay flat: feeding flat, around 16 ft
Shallow bay flat: feeding flat, around 7 ft

Blue Lake (Flathead) 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 Blue Lake (Flathead) specifically, so confirm the current rules before you fish.

Check the official Montana fishing regulations →

Common questions

How deep is Blue Lake (Flathead)?

Blue Lake (Flathead) 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 Blue Lake (Flathead)?

Anglers target walleye, northern pike, yellow perch, smallmouth bass, rainbow trout, lake trout, crappie, channel catfish on Blue Lake (Flathead). 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 Blue Lake (Flathead)?

Shoreline break is the top-rated area: a drop-off in about 23 ft of water that rates prime for walleye in fall. Every other rated spot, per species and season, is on the map above.

When is the best time to fish Blue Lake (Flathead)?

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 Blue Lake (Flathead)?

Fishing on Blue Lake (Flathead) 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

Fish Lake (Lincoln) 2 mi · Big Fire Lake 4 mi · Dickey Lake (Lincoln) 4 mi · Martin Lake (Lincoln) 7 mi · Murphy Lake 7 mi · Upper Whitefish Lake 9 mi · Upper Martin Lake 9 mi · Chain Lake 3 12 mi · Lower Stillwater Lake 13 mi · Frank Lake 15 mi · Long Lake (Lincoln) 15 mi · Rock Lake 16 mi

See how Blue Lake (Flathead) 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: Flathead County fishing maps (55 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.