Tunnel 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 Tunnel 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 Tunnel Lake on the board.

Fishing Tunnel Lake: what the data says

16-acre lake in Teton County, Montana. The lake tops out around 24 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 is how the season plays out for each species, straight from the data behind the map.

The drawn water covers 16 acres wrapped in 0.6 miles of bank. Its 1 shoreline index means few bank features; the contours below do the pattern work. 61% of the surface is littoral (under ~15 ft) — cover, weeds and forage water. Teton County claims this one. If the bite dies, Split Rock Lake is 4 mi to the east.

Arctic Grayling fishing at Tunnel Lake

Come spring, look for arctic grayling tight to the bank in 2 to 10 ft. They move out to 3 to 15 ft in summer and finish the year down in 7 to 24 ft. If you only fish one area, make it Deep basin: a deep basin around 24 ft that scores prime in winter. Best bite is the evening and early morning. A dry fly (parachute adams, elk hair caddis) or a small inline spinner is the honest summer answer here.

Season	Depth	Best window	Start at	Go-to baits
Spring	2 to 10 ft	midday & dusk	open water	1/16 oz spinner (silver), Small dry fly (Adams, Griffith's)
Summer	3 to 15 ft	dusk & dawn	Break off the point (17 ft)	Dry fly (parachute Adams, elk hair caddis), Small inline spinner
Fall	6 to 20 ft	midday	Break off the point (17 ft)	Small spoon, Beadhead nymph under indicator
Winter	7 to 24 ft	midday & dawn	Deep basin (24 ft)	Tungsten jig + waxworm, Small jigging spoon (gold)

Cutthroat Trout fishing at Tunnel Lake

The spring pattern is a shallow one: cutthroat trout in 3 to 15 ft. As the season builds they drop to 7 to 24 ft, wintering in 6 to 24 ft. Top water on the chart: Break off the point, a drop-off in the 17 ft range, prime in summer. 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 (7 ft)	Inline spinner (silver/gold), Small spoon
Summer	7 to 24 ft	dawn & dusk	Break off the point (17 ft)	Trolled spoon (small), Inline spinner
Fall	5 to 24 ft	dawn & dusk	Main-lake point (7 ft)	Casting spoon, Inline spinner
Winter	6 to 24 ft	dawn	Break off the point (17 ft)	Small jigging spoon, Marabou jig

Notable structure

Tunnel Lake carries 3 mapped structure features, topping out (or rather bottoming out) at Deep basin, about 24 ft down.

Deep basin: deep basin, around 24 ft
Break off the point: drop-off, around 17 ft
Main-lake point: point, around 7 ft

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

Check the official Montana fishing regulations →

Common questions

How deep is Tunnel Lake?

Tunnel Lake is about 24 ft (7 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 Tunnel Lake?

Anglers target arctic grayling, cutthroat trout on Tunnel Lake.

Where is the best fishing spot on Tunnel Lake?

Deep basin is the top-rated area: a deep basin in about 24 ft of water that rates prime for arctic grayling in winter. Every other rated spot, per species and season, is on the map above.

When is the best time to fish Tunnel Lake?

For arctic grayling, 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 Tunnel Lake?

Fishing on Tunnel 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

Split Rock Lake 4 mi · Pishkun Reservoir 6 mi · Willow Creek Reservoir 9 mi · Gibson Reservoir 10 mi · Ostle Reservoir 22 mi · Bean Lake 25 mi · Parker Lake 35 mi · Heart Lake (Lewis and Clark) 35 mi · Canyon Lake (Lewis and Clark) 37 mi · Camp Lake (Lewis and Clark) 38 mi · Lake Otatsy 38 mi · Coopers Lake 42 mi

See how Tunnel Lake stacks up: best arctic grayling lakes in Montana · best cutthroat trout lakes in Montana

More water nearby: Teton County fishing maps (5 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.