Harpers 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 Harpers 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 Harpers Lake on the board.

Fishing Harpers Lake: what the data says

18-acre lake in Missoula County, Montana. The lake tops out around 30 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's the year, species by species, as the scoring engine sees it.

Traced from the shoreline, Harpers Lake runs 18 acres with 0.7 miles of edge. Nearly circular (index 1.1), so the story is the bottom, not the bank. The shallow band under 15 ft claims about 48% of the surface — that's where the groceries are. Figure 0.3 mi of water from one end to the other. The water lies in Missoula County. For a second option, Salmon Lake lies 5 mi north.

Yellow Perch fishing at Harpers Lake

Early season yellow perch use the shallows, holding in 3 to 12 ft. Expect a summer slide to 10 to 30 ft, then a winter hold in 9 to 30 ft. Put Deep basin first on the milk run — a deep basin near 30 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	10 to 30 ft	dawn	Deep basin (30 ft)	Drop-shot micro plastics, Small spoon tipped with worm
Fall	9 to 30 ft	midday	Deep basin (30 ft)	Jigging spoon (small), Perch rig / spreader
Winter	9 to 30 ft	midday & dawn	Deep basin (30 ft)	Tungsten jig + spikes, Rattle spoon (small)

Cutthroat Trout fishing at Harpers Lake

Spring cutthroat trout on Harpers Lake hold shallow, usually 3 to 15 ft. They move out to 9 to 30 ft in summer and finish the year down in 8 to 30 ft. Put Break off the point first on the milk run — a drop-off near 21 ft that grades prime for summer. The feeding windows run early morning and the evening. The summer box starts with a trolled spoon (small) or an inline spinner.

Season	Depth	Best window	Start at	Go-to baits
Spring	3 to 15 ft	dawn & dusk	Main-lake point (4 ft)	Inline spinner (silver/gold), Small spoon
Summer	9 to 30 ft	dawn & dusk	Break off the point (21 ft)	Trolled spoon (small), Inline spinner
Fall	5 to 25 ft	dawn & dusk	Main-lake point (4 ft)	Casting spoon, Inline spinner
Winter	8 to 30 ft	dawn	Break off the point (21 ft)	Small jigging spoon, Marabou jig

Rainbow Trout fishing at Harpers Lake

Start shallow in spring: rainbow trout sit in 5 to 20 ft that time of year. Warm water sends them out to 8 to 30 ft; cold water stacks them in 6 to 30 ft. Top water on the chart: Break off the point, a drop-off in the 21 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 (4 ft)	Inline spinner (silver), Small spoon
Summer	8 to 30 ft	dawn & dusk	Break off the point (21 ft)	Dodger + spoon (deep troll), Flutter spoon
Fall	9 to 30 ft	dawn & dusk	Break off the point (21 ft)	Casting spoon, Jerkbait over shoals
Winter	6 to 30 ft	dawn	Break off the point (21 ft)	Jigging spoon, Tube jig (white)

Notable structure

The chart marks 4 structure features on Harpers Lake; the deepest is Deep basin at about 30 ft.

Deep basin: deep basin, around 30 ft
Break off the point: drop-off, around 21 ft
Main-lake point: point, around 4 ft
Secondary point: point, around 2 ft

Public access & boat ramps

Harpers Lake — ramp (gravel)

Access data: Montana FWP — Fishing Access Sites. Confirm conditions and fees locally before you launch.

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

Check the official Montana fishing regulations →

Common questions

How deep is Harpers Lake?

Harpers Lake is about 30 ft (9 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 Harpers Lake?

Anglers target yellow perch, cutthroat trout, rainbow trout on Harpers Lake.

Where is the best fishing spot on Harpers Lake?

Deep basin is the top-rated area: a deep basin in about 30 ft of water that rates prime for yellow perch in fall. The map above holds the full rated-spot list for every species and season.

When is the best time to fish Harpers Lake?

For yellow perch, the summer bite is best in 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 Harpers Lake?

Fishing on Harpers 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

Salmon Lake 5 mi · Upsata Lake 8 mi · Placid Lake 10 mi · Cottonwood Lake, Middle 10 mi · Tuppers Lake 11 mi · Blackfoot River 12 mi · Seeley Lake 13 mi · Pyramid Lake 17 mi · Browns Lake 18 mi · Morrell Lake 19 mi · Camp Lake (Lewis and Clark) 19 mi · Lake Otatsy 20 mi

See how Harpers Lake stacks up: best rainbow trout lakes in Montana · best yellow perch 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.