Diamond Lake (Mineral) 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 Diamond Lake (Mineral)

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Fishing Diamond Lake (Mineral): what the data says

18-acre lake in Mineral County, Montana. The lake tops out around 25 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. What the data behind the map says about each species, season by season:

On the chart, Diamond Lake (Mineral) draws 18 acres inside 0.7 miles of shoreline. At index 1.1 the outline is almost a bowl — read the depth changes, not the shoreline. 45% of the surface is littoral (under ~15 ft) — cover, weeds and forage water. Call it 0.3 mi long. The water lies in Mineral County. Closest neighbour on DepthScout: Cliff Lake (Mineral), 1 mi southwest of here.

Walleye fishing at Diamond Lake (Mineral)

Spring walleye on Diamond Lake (Mineral) hold shallow, usually 4 to 15 ft. They move out to 8 to 25 ft in summer and finish the year down in 8 to 25 ft. Put Break off the point first on the milk run — a drop-off near 16 ft that grades prime for fall. The feeding windows run the evening and early morning. The summer box starts with a crawler harness on bottom bouncer or a deep crankbait (trolled).

Season	Depth	Best window	Start at	Go-to baits
Spring	4 to 15 ft	dusk & dawn	Main-lake point (5 ft)	1/8 oz jig + minnow, Hair jig
Summer	8 to 25 ft	dusk & dawn	Break off the point (16 ft)	Crawler harness on bottom bouncer, Deep crankbait (trolled)
Fall	8 to 25 ft	dusk & night	Break off the point (16 ft)	Jigging rap, Jig + big minnow
Winter	8 to 25 ft	dusk & dawn	Deep basin (24 ft)	Jigging spoon + minnow head, Rattle bait

Northern Pike fishing at Diamond Lake (Mineral)

In spring, northern pike run shallow here, mostly 2 to 8 ft. Summer pushes them deeper, 8 to 20 ft, and winter fish settle into 5 to 15 ft. Break off the point is the standout, a drop-off at roughly 16 ft, rated prime for fall northern pike. Time it for early morning and the evening. You won't need more than a bucktail or a weedless spoon over cabbage most summer days.

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

Yellow Perch fishing at Diamond Lake (Mineral)

Early season yellow perch use the shallows, holding in 3 to 12 ft. Expect a summer slide to 8 to 25 ft, then a winter hold in 8 to 25 ft. Put Deep basin first on the milk run — a deep basin near 24 ft that grades prime for fall. In summer the feeding windows fall in early morning. Tie on a drop-shot micro plastics or a small spoon tipped with worm and you're in the game.

Season	Depth	Best window	Start at	Go-to baits
Spring	3 to 12 ft	midday & dawn	open water	Small jig + curly tail, Perch-pattern micro crank
Summer	8 to 25 ft	dawn	Deep basin (24 ft)	Drop-shot micro plastics, Small spoon tipped with worm
Fall	8 to 25 ft	midday	Deep basin (24 ft)	Jigging spoon (small), Perch rig / spreader
Winter	8 to 25 ft	midday & dawn	Deep basin (24 ft)	Tungsten jig + spikes, Rattle spoon (small)

Smallmouth Bass fishing at Diamond Lake (Mineral)

In spring, smallmouth bass run shallow here, mostly 3 to 12 ft. Summer pushes them deeper, 8 to 25 ft, and winter fish settle into 8 to 25 ft. Break off the point is the standout, a drop-off at roughly 16 ft, rated prime for winter smallmouth bass. Time it for early morning and the evening. You won't need more than a drop shot (goby/minnow) or a ned rig most summer days.

Season	Depth	Best window	Start at	Go-to baits
Spring	3 to 12 ft	dawn & dusk	Main-lake point (5 ft)	Ned rig, Tube jig
Summer	8 to 25 ft	dawn & dusk	Break off the point (16 ft)	Drop shot (goby/minnow), Ned rig
Fall	8 to 25 ft	midday & dawn	Break off the point (16 ft)	Jerkbait, Blade bait
Winter	8 to 25 ft	midday	Break off the point (16 ft)	Blade bait, Hair jig

Rainbow Trout fishing at Diamond Lake (Mineral)

Start shallow in spring: rainbow trout sit in 5 to 20 ft that time of year. Warm water sends them out to 7 to 25 ft; cold water stacks them in 5 to 25 ft. Top water on the chart: Break off the point, a drop-off in the 16 ft range, prime in winter. Fish it in early morning and the evening and you'll meet the bite. Throw a dodger + spoon (deep troll) or a flutter spoon until the fish tell you otherwise.

Season	Depth	Best window	Start at	Go-to baits
Spring	5 to 20 ft	dawn & dusk	Main-lake point (5 ft)	Inline spinner (silver), Small spoon
Summer	7 to 25 ft	dawn & dusk	Break off the point (16 ft)	Dodger + spoon (deep troll), Flutter spoon
Fall	7 to 25 ft	dawn & dusk	Break off the point (16 ft)	Casting spoon, Jerkbait over shoals
Winter	5 to 25 ft	dawn	Break off the point (16 ft)	Jigging spoon, Tube jig (white)

Lake Trout fishing at Diamond Lake (Mineral)

The spring pattern is a shallow one: lake trout in 6 to 25 ft. The depth story barely changes: 8 to 25 ft through summer, 6 to 25 ft in winter. Top water on the chart: Deep basin, a deep basin in the 24 ft range, prime in summer. Time it for early morning. Summer baits: a white tube jig (deep) or a magnum spoon on downrigger gets it done.

Season	Depth	Best window	Start at	Go-to baits
Spring	6 to 25 ft	dawn & dusk	Main-lake point (5 ft)	Casting spoon over shoals, Jerkbait (shallow)
Summer	8 to 25 ft	dawn	Deep basin (24 ft)	White tube jig (deep), Magnum spoon on downrigger
Fall	5 to 25 ft	dusk & dawn	Main-lake point (5 ft)	Heavy casting spoon, Jigging rap over reefs
Winter	6 to 25 ft	dawn	Deep basin (24 ft)	White tube jig, Airplane jig

Diamond Lake (Mineral) 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

4 pieces of structure are mapped here — Deep basin, around 24 ft, is the deepest of them.

Deep basin: deep basin, around 24 ft
Break off the point: drop-off, around 16 ft
Main-lake point: point, around 5 ft
Secondary point: point, around 3 ft

Diamond Lake (Mineral) 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 Diamond Lake (Mineral) specifically, so confirm the current rules before you fish.

Check the official Montana fishing regulations →

Common questions

How deep is Diamond Lake (Mineral)?

Diamond Lake (Mineral) is about 25 ft (8 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 Diamond Lake (Mineral)?

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

Break off the point is the top-rated area: a drop-off in about 16 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 Diamond Lake (Mineral)?

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 Diamond Lake (Mineral)?

Fishing on Diamond Lake (Mineral) 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

Cliff Lake (Mineral) 1 mi · Lost Lake (Mineral) 4 mi · Moore Lake (Mineral) 4 mi · Bonanza Lake, Upper 4 mi · Oregon Lake, Middle 8 mi · Hoodoo Lake 14 mi · Crystal Lake (Mineral) 15 mi · Hidden Lake (Mineral) 17 mi · French Lake 17 mi · Pearl Lake 17 mi · Trio Lakes 18 mi · Crater Lake 21 mi

See how Diamond Lake (Mineral) 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.