Lake Armstrong Depth Map & Fishing Spots (WA)

Hatch outlook

Callibaetis (Speckled Dun)Active window

Typical here: Aug 15 – Sep 15 · the smaller fall brood

nymphthe hours before the midday emergence — nymphs rise off the weed tops in a vertical zigzag that can take hours — sources split between slow 2–4 inch strips with long pauses and a quicker steady retrieve; carry both speeds
dunmidday, roughly 11am into early afternoon
spinnermid-to-late-morning falls

Trout browse the weed-bed edges knocking nymphs loose, then cruise the flats sipping duns at midday — the marquee western lake mayfly.

The midday emergence puts cruisers over weed flats in under 20 ft: a casting bubble with a #14 Callibaetis nymph retrieved dead-slow with pauses is the honest match. Between hatch hours, small spoons and #1 inline spinners along the weed edges and drop-offs pick off the same fish.

The event happens over weed flats and weed-bed edges in 20 ft of water or less

Chironomids (stillwater midges)Active window

Typical here: May 1 – Oct 31

nymphearly morning, start of the day — fish the bloodworm ON the bottom — 4–6 inches off the mud before the emergence starts
pupathe cool morning hours are prime — as the emergence builds, slide the pupa up to 12–15 inches off bottom under the indicator; a little wind chop does the jigging

Concentrates by DEPTH BAND and mud type, not a fixed spot: roughly 20–25 ft in spring, deeper midsummer, in against the feeder creeks in summer heat, 5–25 ft in fall. Match the band.

This one translates almost perfectly: a slip float with a 1/64–1/100 oz midge-pattern jig set 4–15 inches off bottom over a mud flat, dead-sticked with the chop doing the work. Depth control is everything — no moving lure imitates a hanging pupa; the float rig IS the technique.

The event happens over open mud flats alongside weedlines, channels and basin edges; feeder-creek mouths in summer heat

Water boatman fall flightsActive window

Typical here: Aug 25 – Oct 10 · peaks on crisp, bright fall days after the first cold snap

adultmiddday-ish on calm, sunny fall days — the fishable moment is the splashdown: boatmen dive in headfirst trailing an air bubble and make repeated trips back to the surface — a fly or lure that dives nose-first on the drop imitates exactly this

Takes are seldom subtle — trout ravage boatmen as they hit the water and during their subsurface runs.

Tailor-made for hardware: a small 1/16 oz silver-bellied spoon or jig cast AT the rings of a splashdown sinks headfirst exactly like the natural — twitch-pause it back through the top few feet. On flight days fan-cast the shallow weed margins.

The event happens over near-shore shallows, weed beds and shoal margins on calm sunny fall afternoons

Grasshoppers (east-side summer)Active window

Typical here: Jun 15 – Sep 30

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

Next on this water

Damselfly migration · forageMay 15 – Jul 31 · in ~9 months

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 Lake Armstrong

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 Lake Armstrong on the board.

Fishing Lake Armstrong: what the data says

31-acre lake near Bryant. 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. Species by species, here's what the data says the year looks like.

The drawn water covers 31 acres wrapped in 0.9 miles of bank. A shoreline index of 1.2 says round and simple: fish relate to depth changes here, not shoreline features. Roughly 60% of the water is 15 ft or less, the band where the food chain lives. Call it 0.4 mi long by 0.2 mi wide at the broadest reach. It sits in Snohomish County. If the bite dies, Bryant Lake is 1 mi to the west.

Cutthroat Trout fishing at Lake Armstrong

The spring pattern is a shallow one: cutthroat trout in 3 to 15 ft. Midsummer fish sit out in 7 to 24 ft before dropping to 6 to 24 ft for winter. The spot to know is Deep basin, a deep basin in about 24 ft of water that rates prime for cutthroat trout in winter. Plan around early morning and the evening in the warm months. 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	open water	Inline spinner (silver/gold), Small spoon
Summer	7 to 24 ft	dawn & dusk	Deep basin (24 ft)	Trolled spoon (small), Inline spinner
Fall	5 to 24 ft	dawn & dusk	open water	Casting spoon, Inline spinner
Winter	6 to 24 ft	dawn	Deep basin (24 ft)	Small jigging spoon, Marabou jig

Rainbow Trout fishing at Lake Armstrong

When the water first warms, rainbow trout slide up into 5 to 20 ft. By summer they slide out to 6 to 24 ft, and by winter most fish are in 5 to 24 ft. If you only fish one area, make it Deep basin: a deep basin around 24 ft that scores prime in winter. In summer the feeding windows fall in early morning and the evening. Keep a dodger + spoon (deep troll) or a flutter spoon rigged through the warm months.

Season	Depth	Best window	Start at	Go-to baits
Spring	5 to 20 ft	dawn & dusk	Back-bay flat (8 ft)	Inline spinner (silver), Small spoon
Summer	6 to 24 ft	dawn & dusk	Deep basin (24 ft)	Dodger + spoon (deep troll), Flutter spoon
Fall	7 to 24 ft	dawn & dusk	Deep basin (24 ft)	Casting spoon, Jerkbait over shoals
Winter	5 to 24 ft	dawn	Deep basin (24 ft)	Jigging spoon, Tube jig (white)

Notable structure

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

Deep basin: deep basin, around 24 ft
Back-bay flat: weed flat, around 8 ft
Shallow bay flat: weed flat, around 3 ft

Public access & boat ramps

Lake Armstrong — ramp (concrete)

Access data: Washington WDFW — Water Access Sites. Confirm conditions and fees locally before you launch.

Lake Armstrong stocking report

Date	Species	Count	Size
Apr 22	Rainbow trout	2,700	—
Apr 3	Cutthroat trout	62	—

Source: WDFW fish-stocking reports, retrieved 2026-08-18.

Lake Armstrong fishing regulations

Season dates, license requirements, and size and bag limits for Washington waters are set by the Washington Department of Fish and Wildlife — and special regulations can apply to Lake Armstrong specifically, so confirm the current rules before you fish.

Check the official Washington fishing regulations →

Common questions

How deep is Lake Armstrong?

Lake Armstrong 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 Lake Armstrong?

Anglers target cutthroat trout, rainbow trout on Lake Armstrong.

Where is the best fishing spot on Lake Armstrong?

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

When is the best time to fish Lake Armstrong?

For cutthroat trout, the summer bite is best in early morning and the evening. Each species page section below lists the seasonal windows, and the map shows a live NOW badge when you're inside one.

Is Lake Armstrong stocked with fish?

Yes — per WDFW fish-stocking reports records, Lake Armstrong was most recently stocked Apr 22 with 2,700 rainbow trout. The full stocking history is listed above.

What are the fishing regulations for Lake Armstrong?

Fishing on Lake Armstrong is regulated by the Washington Department of Fish and Wildlife. Check the official Washington regulations for current license requirements, season dates, and size and bag limits — special regulations can apply to this specific water.

Nearby waters

Bryant Lake 1 mi · Sunday Lake 6 mi · Lake McMurray 8 mi · Riley Lake 8 mi · Lake Ki 8 mi · Lake Cavanaugh 8 mi · Lake Loma 9 mi · Crabapple Lake 10 mi · Lake Goodwin 10 mi · Lake Howard 11 mi · Lake Shoecraft 11 mi · Lake Martha 11 mi

See how Lake Armstrong stacks up: best rainbow trout lakes in Washington · best cutthroat trout lakes in Washington

More water nearby: Snohomish County fishing maps (28 charts). Browse all Washington 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.