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Rating depth structure for smallmouth bass.
Recent public catches load as you reach this section.
12-acre lake in Carbon County, Montana. The lake tops out around 35 ft. The depth chart comes from published agency bathymetric survey data, so the contours are survey-derived rather than computer-modeled. Here is how the season plays out for each species, straight from the data behind the map.
The drawn water covers 12 acres wrapped in 0.6 miles of bank. A shoreline index of 1.2 says round and simple: fish relate to depth changes here, not shoreline features. About 63% of the surface sits shallower than 15 ft — that's the weed-and-bait zone. It sits in Carbon County. If the bite dies, Glacier Lake is 1 mi to the southeast.
Start shallow in spring: walleye sit in 4 to 15 ft that time of year. Warm water sends them out to 15 to 35 ft; cold water stacks them in 11 to 35 ft. Top water on the chart: Deep basin, a deep basin in the 33 ft range, prime in winter. Fish it in the evening and early morning and you'll meet the bite. Throw a crawler harness on bottom bouncer or a deep crankbait (trolled) until the fish tell you otherwise.
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 | 4 to 15 ft | dusk & dawn | Shoreline break (8 ft) | 1/8 oz jig + minnow, Hair jig |
| Summer | 15 to 35 ft | dusk & dawn | Deep basin (33 ft) | Crawler harness on bottom bouncer, Deep crankbait (trolled) |
| Fall | 11 to 35 ft chart-limited; documented 12 to 40 ft | dusk & night | Shoreline break (8 ft) | Jigging rap, Jig + big minnow |
| Winter | 11 to 35 ft chart-limited; documented 20 to 40 ft | dusk & dawn | Deep basin (33 ft) | Jigging spoon + minnow head, Rattle bait |
Spring northern pike on Triangle Lake (Carbon) hold shallow, usually 2 to 8 ft. They move out to 8 to 20 ft in summer and finish the year down in 5 to 15 ft. Put Shallow bay flat first on the milk run — a weed flat near 4 ft that grades prime for spring. The feeding windows run early morning and the evening. The summer box starts with a bucktail or a weedless spoon over cabbage.
| Season | Depth | Best window | Start at | Go-to baits |
|---|---|---|---|---|
| Spring | 2 to 8 ft | midday & dawn | Shallow bay flat (4 ft) | #5 inline spinner, Spoon (red/white) |
| Summer | 8 to 20 ft | dawn & dusk | Shoreline break (8 ft) | Bucktail, Weedless spoon over cabbage |
| Fall | 6 to 18 ft | midday & dawn | Shoreline break (8 ft) | Big rubber (Bull Dawg style), Husky-style jerkbait |
| Winter | 5 to 15 ft | midday | Shallow bay flat (4 ft) | Tip-ups, Large jigging spoon |
Spring puts yellow perch in skinny water — 3 to 12 ft is the zone. Warm water sends them out to 10 to 30 ft; cold water stacks them in 15 to 35 ft. Shallow bay flat is the standout, a weed flat at roughly 4 ft, rated prime for spring yellow perch. Plan around early morning in the warm months. A drop-shot micro plastics or a small spoon tipped with worm covers the summer program.
| Season | Depth | Best window | Start at | Go-to baits |
|---|---|---|---|---|
| Spring | 3 to 12 ft | midday & dawn | Shallow bay flat (4 ft) | Small jig + curly tail, Perch-pattern micro crank |
| Summer | 10 to 30 ft | dawn | Shoreline break (8 ft) | Drop-shot micro plastics, Small spoon tipped with worm |
| Fall | 12 to 35 ft | midday | Deep basin (33 ft) | Jigging spoon (small), Perch rig / spreader |
| Winter | 15 to 35 ft | midday & dawn | Deep basin (33 ft) | Tungsten jig + spikes, Rattle spoon (small) |
Spring smallmouth bass on Triangle Lake (Carbon) hold shallow, usually 3 to 12 ft. They move out to 10 to 30 ft in summer and finish the year down in 11 to 35 ft. Put Shoreline break first on the milk run — a drop-off near 8 ft that grades prime for fall. The feeding windows run early morning and the evening. The summer box starts with a drop shot (goby/minnow) or a ned rig.
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 | 3 to 12 ft | dawn & dusk | open water | Ned rig, Tube jig |
| Summer | 10 to 30 ft | dawn & dusk | Shoreline break (8 ft) | Drop shot (goby/minnow), Ned rig |
| Fall | 8 to 25 ft | midday & dawn | Shoreline break (8 ft) | Jerkbait, Blade bait |
| Winter | 11 to 35 ft chart-limited; documented 20 to 45 ft | midday | Shoreline break (8 ft) | Blade bait, Hair jig |
Come spring, look for rainbow trout tight to the bank in 5 to 20 ft. Expect a summer slide to 8 to 30 ft, then a winter hold in 7 to 35 ft. Start at Shoreline break. It's a drop-off holding about 8 ft of water and rates prime come winter. Prime time lands in early morning and the evening. A dodger + spoon (deep troll) or a flutter spoon is the honest summer answer here.
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 | 5 to 20 ft | dawn & dusk | Shoreline break (8 ft) | Inline spinner (silver), Small spoon |
| Summer | 8 to 30 ft | dawn & dusk | Shoreline break (8 ft) | Dodger + spoon (deep troll), Flutter spoon |
| Fall | 10 to 35 ft | dawn & dusk | Shoreline break (8 ft) | Casting spoon, Jerkbait over shoals |
| Winter | 7 to 35 ft chart-limited; documented 8 to 40 ft | dawn | Shoreline break (8 ft) | Jigging spoon, Tube jig (white) |
Early season lake trout use the shallows, holding in 9 to 35 ft. Even in summer they hold at 11 to 35 ft; winter keeps them in 9 to 35 ft. Put Deep basin first on the milk run — a deep basin near 33 ft that grades prime for summer. In summer the feeding windows fall in early morning. Tie on a white tube jig (deep) or a magnum spoon on downrigger and you're in the game.
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 | 9 to 35 ft chart-limited; documented 10 to 40 ft | dawn & dusk | Shoreline break (8 ft) | Casting spoon over shoals, Jerkbait (shallow) |
| Summer | 11 to 35 ft chart-limited; documented 50 to 120 ft | dawn | Deep basin (33 ft) | White tube jig (deep), Magnum spoon on downrigger |
| Fall | 7 to 35 ft chart-limited; documented 10 to 50 ft | dusk & dawn | Shoreline break (8 ft) | Heavy casting spoon, Jigging rap over reefs |
| Winter | 9 to 35 ft chart-limited; documented 20 to 80 ft | dawn | Deep basin (33 ft) | White tube jig, Airplane jig |
Triangle Lake (Carbon) also holds crappie (10 to 25 ft in summer), channel catfish (8 to 25 ft in summer), cutthroat trout (10 to 35 ft in summer). Pick any of them on the map above for rated spots and bait picks.
Structure-wise the chart holds 4 features, led in depth by Deep basin at roughly 33 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 Triangle Lake (Carbon) specifically, so confirm the current rules before you fish.
Check the official Montana fishing regulations →
Triangle Lake (Carbon) is about 35 ft (11 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 walleye, northern pike, yellow perch, smallmouth bass, rainbow trout, lake trout, crappie, channel catfish, cutthroat trout on Triangle Lake (Carbon). This isn't a survey of the water — none is published for it — but an informed estimate from the species common to the region, narrowed by this water's depth, size and each species' range.
Deep basin is the top-rated area: a deep basin in about 33 ft of water that rates prime for walleye in winter. Open the map above to see every rated spot for each species and season.
For walleye, 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.
Fishing on Triangle Lake (Carbon) 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.
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See how Triangle Lake (Carbon) 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: Carbon County fishing maps (65 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.