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Rating depth structure for rainbow trout.
Recent public catches load as you reach this section.
845-acre lake in East Kootenay Regional District, British Columbia. The lake tops out around 69 ft. The contours come from a model of the real basin shape and its known max depth. Read them as probabilities, not soundings, and keep them out of navigation decisions. The rest of this page walks each species through its year, using the map's own scoring.
Traced from the shoreline, St. Mary Lake runs 845 acres with 8.1 miles of edge, with 3 islands in the mix. The shoreline is moderately structured (index 2) — enough points and pockets to pattern. The shallow band under 15 ft claims about 42% of the surface on the model — that's where the groceries are. End to end it runs roughly 2.4 mi, about 0.9 mi across. You'll find it in East Kootenay Regional District. The nearest mapped water is Kiakho Lakes, 16 mi to the southeast.
In spring, burbot run shallow here, mostly 21 to 69 ft. Summer keeps them at 21 to 69 ft, and they winter in 15 to 60 ft. Spring burbot concentrate at Deep basin, a prime-rated deep basin around 59 ft. Fish it in after dark and midday and you'll meet the bite. You won't need more than a heavy jig + cut bait most summer days.
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 | 21 to 69 ft chart-limited; documented 25 to 70 ft | night & dusk | Deep basin (59 ft) | Glow jigging spoon + cut bait, Rattle bait (dark) |
| Summer | 21 to 69 ft chart-limited; documented 50 to 120 ft | night & midday | Deep basin (59 ft) | Heavy jig + cut bait |
| Fall | 21 to 69 ft chart-limited; documented 30 to 80 ft | night & dusk | Deep basin (59 ft) | Glow spoon + minnow head, Blade bait (slow) |
| Winter | 15 to 60 ft | night & dusk | Deep basin (59 ft) | Glow tungsten + cut bait, Rattle spoon + minnow head |
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 Break off the point: a drop-off around 31 ft that scores prime in summer. 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 (17 ft) | Inline spinner (silver/gold), Small spoon |
| Summer | 10 to 35 ft | dawn & dusk | Break off the point (31 ft) | Trolled spoon (small), Inline spinner |
| Fall | 5 to 25 ft | dawn & dusk | Main-lake point (17 ft) | Casting spoon, Inline spinner |
| Winter | 10 to 40 ft | dawn | Break off the point (31 ft) | Small jigging spoon, Marabou jig |
Spring puts kokanee in skinny water — 10 to 30 ft is the zone. As the season builds they drop to 21 to 69 ft, wintering in 17 to 69 ft. Summer kokanee concentrate at Deep basin, a prime-rated deep basin around 59 ft. Warm-month bites cluster around early morning. A dodger + pink/orange squid on downrigger or a kokanee bug + corn 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 30 ft | dawn | Break off the point (31 ft) | Small dodger + squid (pink), Wedding-ring spinner + corn |
| Summer | 21 to 69 ft chart-limited; documented 30 to 70 ft | dawn | Deep basin (59 ft) | Dodger + pink/orange squid on downrigger, Kokanee bug + corn |
| Fall | 5 to 40 ft | dawn | Break off the point (31 ft) | Dodger + squid (deeper red/purple), Small spoon |
| Winter | 17 to 69 ft chart-limited; documented 20 to 80 ft | dawn | Deep basin (59 ft) | Small glow jig + corn or maggot, Tiny spoon |
In spring, rainbow trout run shallow here, mostly 5 to 20 ft. Summer pushes them deeper, 8 to 30 ft, and winter fish settle into 8 to 40 ft. Break off the point is the standout, a drop-off at roughly 31 ft, rated prime for winter rainbow trout. Time it for early morning and the evening. You won't need more than a dodger + spoon (deep troll) or a flutter spoon most summer days.
| Season | Depth | Best window | Start at | Go-to baits |
|---|---|---|---|---|
| Spring | 5 to 20 ft | dawn & dusk | Main-lake point (17 ft) | Inline spinner (silver), Small spoon |
| Summer | 8 to 30 ft | dawn & dusk | Break off the point (31 ft) | Dodger + spoon (deep troll), Flutter spoon |
| Fall | 10 to 35 ft | dawn & dusk | Main-lake point (17 ft) | Casting spoon, Jerkbait over shoals |
| Winter | 8 to 40 ft | dawn | Break off the point (31 ft) | Jigging spoon, Tube jig (white) |
Spring lake whitefish on St. Mary Lake hold shallow, usually 15 to 45 ft. They move out to 21 to 69 ft in summer and finish the year down in 21 to 69 ft. Put Deep basin first on the milk run — a deep basin near 59 ft that grades prime for summer. The feeding windows run early morning. The summer box starts with a blade bait vertical or a small jigging spoon.
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 | 15 to 45 ft | midday & dawn | Break off the point (31 ft) | Small jig + waxworm, Blade bait (small) |
| Summer | 21 to 69 ft chart-limited; documented 40 to 90 ft | dawn | Deep basin (59 ft) | Blade bait vertical, Small jigging spoon |
| Fall | 8 to 30 ft | dusk | Break off the point (31 ft) | Small spoon (gold), Jig + plastic larva |
| Winter | 21 to 69 ft chart-limited; documented 25 to 70 ft | midday & dawn | Deep basin (59 ft) | Jigging spoon + bead chain, Tungsten jig + waxie |
Spring puts bull trout in skinny water — 10 to 40 ft is the zone. Warm water sends them out to 21 to 69 ft; cold water stacks them in 20 to 69 ft. Deep basin is the standout, a deep basin at roughly 59 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 | Break off the point (31 ft) | Large jointed plug, 6" swimbait (kokanee/trout pattern) |
| Summer | 21 to 69 ft chart-limited; documented 30 to 90 ft | dawn & dusk | Deep basin (59 ft) | Trolled plug on downrigger, Heavy jigging spoon |
| Fall | 5 to 35 ft | dawn & dusk | Main-lake point (17 ft) | Large glide bait, Jointed plug |
| Winter | 20 to 69 ft chart-limited; documented 20 to 70 ft | dawn | Break off the point (31 ft) | Heavy spoon (slow lift), Large soft swimbait |
St. Mary Lake also holds dolly varden (2 to 40 ft in summer). Pick any of them on the map above for rated spots and bait picks.
Structure-wise the chart holds 6 features, led in depth by Deep basin at roughly 59 ft.
Season dates, license requirements, and size and bag limits for British Columbia waters are set by the BC freshwater fishing synopsis — and special regulations can apply to St. Mary Lake specifically, so confirm the current rules before you fish.
Check the official British Columbia fishing regulations →
St. Mary Lake is about 69 ft (21 m) deep at its deepest point. The contours here are modeled from the water's real shape and maximum depth, so treat them as a rough guide.
Anglers target burbot, cutthroat trout, kokanee, rainbow trout, lake whitefish, bull trout, dolly varden on St. Mary Lake.
Deep basin is the top-rated area: a deep basin in about 59 ft of water that rates prime for burbot in spring. The map above holds the full rated-spot list for every species and season.
For burbot, the summer bite is best in after dark and midday. Each species page section below lists the seasonal windows, and the map shows a live NOW badge when you're inside one.
Fishing on St. Mary Lake is regulated by the BC freshwater fishing synopsis. Check the official British Columbia regulations for current license requirements, season dates, and size and bag limits — special regulations can apply to this specific water.
Kiakho Lakes 16 mi · New Lake 17 mi · Jim Smith Lake 18 mi · Hahas Lake 19 mi · Ta Ta Lake 21 mi · Monroe Lake 23 mi · Hiawatha Lake 23 mi · Mcnair Lakes 23 mi · Wasa Lake 24 mi · Mineral Lake 24 mi · Mcnair Lakes 24 mi · Moyie Lake 24 mi
See how St. Mary Lake stacks up: best rainbow trout lakes in British Columbia · best kokanee lakes in British Columbia · best lake whitefish lakes in British Columbia · best burbot lakes in British Columbia
More water nearby: East Kootenay Regional District fishing maps (89 charts). Browse all British Columbia fishing maps. See every water on DepthScout. 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.