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11-acre lake in Park County, Montana. The lake tops out around 90 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.
The drawn water covers 10 acres wrapped in 0.5 miles of bank. At index 1.2 the outline is almost a bowl — read the depth changes, not the shoreline. About 14% of the surface sits shallower than 15 ft — that's the weed-and-bait zone. It sits in Park County. Its nearest charted neighbour, Glacier Green Lake, is 1 mi to the northwest.
Early season brook trout use the shallows, holding in 2 to 15 ft. Expect a summer slide to 10 to 30 ft, then a winter hold in 3 to 20 ft. In summer the feeding windows fall in early morning and the evening. Tie on a small spoon fished deep or a trolled lake-clear wobbler + worm and you're in the game.
| Season | Depth | Best window | Start at | Go-to baits |
|---|---|---|---|---|
| Spring | 2 to 15 ft | dawn & dusk | open water | Small inline spinner (gold), Tiny spoon |
| Summer | 10 to 30 ft | dawn & dusk | open water | Small spoon fished deep, Trolled lake-clear wobbler + worm |
| Fall | 2 to 15 ft | midday & dawn | open water | Small spoon (orange), Spinner |
| Winter | 3 to 20 ft | dawn | open water | Small jigging spoon, Tungsten jig + plastic |
When the water first warms, lake trout slide up into 10 to 40 ft. By summer they slide out to 27 to 90 ft, and by winter most fish are in 20 to 80 ft. If you only fish one area, make it Deep basin: a deep basin around 90 ft that scores prime in summer. In summer the feeding windows fall in early morning. Keep a white tube jig (deep) or a magnum spoon on downrigger rigged through the warm months.
| Season | Depth | Best window | Start at | Go-to baits |
|---|---|---|---|---|
| Spring | 10 to 40 ft | dawn & dusk | Main-lake point (23 ft) | Casting spoon over shoals, Jerkbait (shallow) |
| Summer | 27 to 90 ft | dawn | Deep basin (90 ft) | White tube jig (deep), Magnum spoon on downrigger |
| Fall | 10 to 50 ft | dusk & dawn | Main-lake point (23 ft) | Heavy casting spoon, Jigging rap over reefs |
| Winter | 20 to 80 ft | dawn | Break off the point (52 ft) | White tube jig, Airplane jig |
Spring rainbow trout on Cavity Lake hold shallow, usually 5 to 20 ft. By summer they slide out to 8 to 30 ft, and by winter most fish are in 8 to 40 ft. The chart's best answer is Main-lake point — point, 23 ft, prime for fall. Prime time lands in early morning and the evening. The summer box starts with a dodger + spoon (deep troll) or a flutter spoon.
| Season | Depth | Best window | Start at | Go-to baits |
|---|---|---|---|---|
| Spring | 5 to 20 ft | dawn & dusk | Main-lake point (23 ft) | Inline spinner (silver), Small spoon |
| Summer | 8 to 30 ft | dawn & dusk | Main-lake point (23 ft) | Dodger + spoon (deep troll), Flutter spoon |
| Fall | 10 to 35 ft | dawn & dusk | Main-lake point (23 ft) | Casting spoon, Jerkbait over shoals |
| Winter | 8 to 40 ft | dawn | Break off the point (52 ft) | Jigging spoon, Tube jig (white) |
In spring, cutthroat trout run shallow here, mostly 3 to 15 ft. Midsummer fish sit out in 10 to 35 ft before dropping to 10 to 40 ft for winter. Fall cutthroat trout concentrate at Main-lake point, a prime-rated point around 23 ft. Fish it in early morning and the evening and you'll meet the bite. You won't need more than a trolled spoon (small) or an inline spinner most summer days.
| 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 | 10 to 35 ft | dawn & dusk | Main-lake point (23 ft) | Trolled spoon (small), Inline spinner |
| Fall | 5 to 25 ft | dawn & dusk | Main-lake point (23 ft) | Casting spoon, Inline spinner |
| Winter | 10 to 40 ft | dawn | Main-lake point (23 ft) | Small jigging spoon, Marabou jig |
In spring, walleye run shallow here, mostly 4 to 15 ft. Midsummer fish sit out in 15 to 35 ft before dropping to 20 to 40 ft for winter. Fall walleye concentrate at Main-lake point, a prime-rated point around 23 ft. Fish it in the evening and early morning and you'll meet the bite. You won't need more than a crawler harness on bottom bouncer or a deep crankbait (trolled) most summer days.
| Season | Depth | Best window | Start at | Go-to baits |
|---|---|---|---|---|
| Spring | 4 to 15 ft | dusk & dawn | open water | 1/8 oz jig + minnow, Hair jig |
| Summer | 15 to 35 ft | dusk & dawn | Main-lake point (23 ft) | Crawler harness on bottom bouncer, Deep crankbait (trolled) |
| Fall | 12 to 40 ft | dusk & night | Main-lake point (23 ft) | Jigging rap, Jig + big minnow |
| Winter | 20 to 40 ft | dusk & dawn | Main-lake point (23 ft) | Jigging spoon + minnow head, Rattle bait |
The spring pattern is a shallow one: yellow perch in 3 to 12 ft. Midsummer fish sit out in 10 to 30 ft before dropping to 15 to 35 ft for winter. The spot to know is Deep basin, a deep basin in about 90 ft of water that rates good for yellow perch in fall. Plan around early morning in the warm months. Summer baits: a drop-shot micro plastics or a small spoon tipped with worm gets it done.
| 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 (90 ft) | Drop-shot micro plastics, Small spoon tipped with worm |
| Fall | 12 to 35 ft | midday | Deep basin (90 ft) | Jigging spoon (small), Perch rig / spreader |
| Winter | 15 to 35 ft | midday & dawn | Deep basin (90 ft) | Tungsten jig + spikes, Rattle spoon (small) |
Cavity Lake also holds northern pike (8 to 20 ft in summer), smallmouth bass (10 to 30 ft in summer), 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.
3 pieces of structure are mapped here — Deep basin, around 90 ft, is the deepest of them.
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 Cavity Lake specifically, so confirm the current rules before you fish.
Check the official Montana fishing regulations →
Cavity Lake is about 90 ft (27 m) deep at its deepest point. The depth chart here comes from real state fisheries GPS surveys, so the contours reflect measured depths.
Anglers target brook trout, lake trout, rainbow trout, cutthroat trout, walleye, yellow perch, northern pike, smallmouth bass, crappie, channel catfish on Cavity Lake. This isn't a survey of the lake — none is on record for it — but an informed estimate from the species listed for the nearest surveyed lakes in the region, filtered to this lake's depth and habitat.
Deep basin is the top-rated area: a deep basin in about 90 ft of water that rates prime for lake trout in summer. Open the map above to see every rated spot for each species and season.
For brook 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.
Fishing on Cavity 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.
Glacier Green Lake 1 mi · Goose Lake 1 mi · Courthouse Lake 2 mi · Zimmer Lake 2 mi · Wrong Lake 2 mi · Imelda Lake 2 mi · Anvil Lake (Park) 3 mi · Huckleberry Lake 3 mi · Aero Lake, Lower 3 mi · Long Lake (Park) 4 mi · Aero Lake, Upper 4 mi · Round Lake 4 mi
See how Cavity Lake 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: Park County fishing maps (31 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.