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280-acre lake in Powell County, Montana. The lake tops out around 70 ft. The depth chart comes from published agency bathymetric survey data, so the contours are survey-derived rather than computer-modeled. What the data behind the map says about each species, season by season:
Drawn out, this is 280 acres of water rimmed by 3 miles of bank. A shoreline index of 1.3 says round and simple: fish relate to depth changes here, not shoreline features. 10% of the surface is littoral (under ~15 ft) — cover, weeds and forage water. End to end it runs roughly 1.3 mi, about 0.5 mi across. You'll find it in Powell County. Closest neighbour on DepthScout: Lake Otatsy, 8 mi northwest of here.
Spring puts brook trout in skinny water — 2 to 15 ft is the zone. As the season builds they drop to 10 to 30 ft, wintering in 3 to 20 ft. Spring brook trout concentrate at Main-lake point, a prime-rated point around 14 ft. Warm-month bites cluster around early morning and the evening. A small spoon fished deep or a trolled lake-clear wobbler + worm covers the summer program.
| Season | Depth | Best window | Start at | Go-to baits |
|---|---|---|---|---|
| Spring | 2 to 15 ft | dawn & dusk | Main-lake point (14 ft) | 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 | Main-lake point (14 ft) | Small spoon (orange), Spinner |
| Winter | 3 to 20 ft | dawn | Shallow bay flat (15 ft) | Small jigging spoon, Tungsten jig + plastic |
When the water first warms, cutthroat trout slide up into 3 to 15 ft. By summer they slide out to 10 to 35 ft, and by winter most fish are in 10 to 40 ft. If you only fish one area, make it Main-lake point: a point around 14 ft that scores prime in fall. In summer the feeding windows fall in early morning and the evening. Keep a trolled spoon (small) or an inline spinner rigged through the warm months.
| Season | Depth | Best window | Start at | Go-to baits |
|---|---|---|---|---|
| Spring | 3 to 15 ft | dawn & dusk | Main-lake point (14 ft) | Inline spinner (silver/gold), Small spoon |
| Summer | 10 to 35 ft | dawn & dusk | Main-lake point (14 ft) | Trolled spoon (small), Inline spinner |
| Fall | 5 to 25 ft | dawn & dusk | Main-lake point (14 ft) | Casting spoon, Inline spinner |
| Winter | 10 to 40 ft | dawn | Main-lake point (14 ft) | Small jigging spoon, Marabou jig |
Spring puts bull trout in skinny water — 10 to 40 ft is the zone. Warm water sends them out to 21 to 70 ft; cold water stacks them in 20 to 70 ft. Deep basin is the standout, a deep basin at roughly 68 ft, rated prime for summer bull trout. Plan around early morning and the evening in the warm months. A trolled plug on downrigger or a heavy jigging spoon covers the summer program.
Depth note: when a documented seasonal range extends below this chart, the table shows the deepest mapped working water, not a verified holding depth.
| Season | Depth | Best window | Start at | Go-to baits |
|---|---|---|---|---|
| Spring | 10 to 40 ft | dawn & dusk | Main-lake point (14 ft) | Large jointed plug, 6" swimbait (kokanee/trout pattern) |
| Summer | 21 to 70 ft chart-limited; documented 30 to 90 ft | dawn & dusk | Deep basin (68 ft) | Trolled plug on downrigger, Heavy jigging spoon |
| Fall | 5 to 35 ft | dawn & dusk | Main-lake point (14 ft) | Large glide bait, Jointed plug |
| Winter | 20 to 70 ft | dawn | Break off the point (60 ft) | Heavy spoon (slow lift), Large soft swimbait |
Structure-wise the chart holds 6 features, led in depth by Deep basin at roughly 68 ft.
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 Coopers Lake specifically, so confirm the current rules before you fish.
Check the official Montana fishing regulations →
Coopers Lake is about 70 ft (21 m) deep at its deepest point. The depth chart comes from published agency bathymetric survey data, so the contours are survey-derived rather than computer-modeled.
Anglers target brook trout, cutthroat trout, bull trout on Coopers Lake.
Deep basin is the top-rated area: a deep basin in about 68 ft of water that rates prime for bull 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 Coopers 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.
Lake Otatsy 8 mi · Canyon Lake (Lewis and Clark) 9 mi · Camp Lake (Lewis and Clark) 9 mi · Browns Lake 10 mi · Parker Lake 10 mi · Blackfoot River 13 mi · Heart Lake (Lewis and Clark) 13 mi · Upsata Lake 14 mi · Nevada Reservoir 21 mi · Cottonwood Lake, Middle 21 mi · Harpers Lake 22 mi · Salmon Lake 23 mi
See how Coopers Lake stacks up: best brook trout lakes in Montana · best cutthroat trout lakes in Montana
More water nearby: Powell County fishing maps (8 charts). Browse all Montana fishing maps. See every water on DepthScout. Bathymetry: published agency survey data. 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.