Sylvia 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 Sylvia 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 Sylvia Lake on the board.

Fishing Sylvia Lake: what the data says

23-acre lake in Flathead County, Montana. The lake tops out around 43 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. Every species below gets its seasonal read from the same numbers driving the chart.

Sylvia Lake maps at 24 acres behind 1 miles of shoreline. A middling shoreline index (1.5) gives it some bays to work without being a maze. Roughly 30% of the water is 15 ft or less, the band where the food chain lives. Tip to tip the water measures near 0.4 mi with a 0.2-mi widest point. Flathead County claims this one. Its nearest charted neighbour, Island Lake, is 10 mi to the southwest.

Arctic Grayling fishing at Sylvia 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 8 to 25 ft. If you only fish one area, make it Shallow bay flat: a weed flat around 6 ft that scores good in spring. 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	Shallow bay flat (6 ft)	1/16 oz spinner (silver), Small dry fly (Adams, Griffith's)
Summer	3 to 15 ft	dusk & dawn	Shallow bay flat (6 ft)	Dry fly (parachute Adams, elk hair caddis), Small inline spinner
Fall	6 to 20 ft	midday	Break off the point (34 ft)	Small spoon, Beadhead nymph under indicator
Winter	8 to 25 ft	midday & dawn	Deep basin (43 ft)	Tungsten jig + waxworm, Small jigging spoon (gold)

Cutthroat Trout fishing at Sylvia Lake

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: Break off the point, a drop-off in the 34 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 (18 ft)	Inline spinner (silver/gold), Small spoon
Summer	10 to 35 ft	dawn & dusk	Break off the point (34 ft)	Trolled spoon (small), Inline spinner
Fall	5 to 25 ft	dawn & dusk	Main-lake point (18 ft)	Casting spoon, Inline spinner
Winter	10 to 40 ft	dawn	Break off the point (34 ft)	Small jigging spoon, Marabou jig

Notable structure

4 pieces of structure are mapped here — Deep basin, around 43 ft, is the deepest of them.

Deep basin: deep basin, around 43 ft
Break off the point: drop-off, around 34 ft
Main-lake point: point, around 18 ft
Shallow bay flat: weed flat, around 6 ft

Public access & boat ramps

Boat launch — ramp (unpaved)

Access data: OpenStreetMap contributors (ODbL) — community-mapped launches. Confirm conditions and fees locally before you launch.

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

Check the official Montana fishing regulations →

Common questions

How deep is Sylvia Lake?

Sylvia Lake is about 43 ft (13 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 Sylvia Lake?

Anglers target arctic grayling, cutthroat trout on Sylvia Lake.

Where is the best fishing spot on Sylvia Lake?

Break off the point is the top-rated area: a drop-off in about 34 ft of water that rates prime for cutthroat trout in summer. The map above holds the full rated-spot list for every species and season.

When is the best time to fish Sylvia 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 Sylvia Lake?

Fishing on Sylvia 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

Island Lake 10 mi · Tally Lake 13 mi · Ashley Lake 13 mi · Bootjack Lake (Flathead) 16 mi · Little Bitterroot Lake 16 mi · Upper Martin Lake 17 mi · Lower Stillwater Lake 17 mi · Murray Lake 18 mi · Spencer Lake 19 mi · Beaver Lake 19 mi · Big Fire Lake 19 mi · Little Beaver Lake 20 mi

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