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Rating depth structure for largemouth bass.
Shared by DepthScout anglers. Exact spots stay private, always.
982-acre lake near Acton. The lake tops out around 88 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.
Drawn out, this is 980 acres of water rimmed by 22.3 miles of bank, broken up by 8 islands. An index of 5.1 puts the bank firmly in maze territory: point after pocket after cove, every one a casting target. Littoral water — the productive band under ~15 ft — makes up 48% of this chart. End to end it runs roughly 4.5 mi, about 1.4 mi across. You'll find it in York County. The nearest mapped water is Square Pond, 3 mi to the northwest.
In spring, crappie run shallow here, mostly 2 to 8 ft. Midsummer fish sit out in 10 to 25 ft before dropping to 15 to 35 ft for winter. Spring crappie concentrate at Back-bay flat, a prime-rated weed flat around 5 ft. Fish it in early morning and the evening and you'll meet the bite. You won't need more than a jig trolled/spider-rigged or a small crankbait (trolled) most summer days.
| Season | Depth | Best window | Start at | Go-to baits |
|---|---|---|---|---|
| Spring | 2 to 8 ft | midday & dawn | Back-bay flat (5 ft) | 1/16 oz jig + tube, Curly-tail grub |
| Summer | 10 to 25 ft | dawn & dusk | Shallow bay flat (13 ft) | Jig trolled/spider-rigged, Small crankbait (trolled) |
| Fall | 8 to 20 ft | dawn | Shallow bay flat (13 ft) | Jig + minnow combo, Small swimbait (1.5-2") |
| Winter | 15 to 35 ft | midday | Deep basin (79 ft) | Tungsten jig + soft plastic, Tiny jigging spoon |
The spring pattern is a shallow one: brook trout in 2 to 15 ft. As the season builds they drop to 10 to 30 ft, wintering in 3 to 20 ft. Top water on the chart: Pump Box Brook inflow, an inflow / creek mouth in the 5 ft range, prime in spring. Time it for early morning and the evening. Summer baits: a small spoon fished deep or a trolled lake-clear wobbler + worm gets it done.
| Season | Depth | Best window | Start at | Go-to baits |
|---|---|---|---|---|
| Spring | 2 to 15 ft | dawn & dusk | Pump Box Brook inflow (5 ft) | Small inline spinner (gold), Tiny spoon |
| Summer | 10 to 30 ft | dawn & dusk | Pump Box Brook inflow (5 ft) | Small spoon fished deep, Trolled lake-clear wobbler + worm |
| Fall | 2 to 15 ft | midday & dawn | Pump Box Brook inflow (5 ft) | Small spoon (orange), Spinner |
| Winter | 3 to 20 ft | dawn | Pump Box Brook inflow (5 ft) | Small jigging spoon, Tungsten jig + plastic |
Spring brown trout on Mousam Lake hold shallow, usually 3 to 25 ft. By summer they slide out to 25 to 60 ft, and by winter most fish are in 5 to 35 ft. The chart's best answer is Pump Box Brook inflow — inflow / creek mouth, 5 ft, prime for spring. Prime time lands in after dark and early morning. The summer box starts with a spoon at the thermocline or a deep stickbait (night).
| Season | Depth | Best window | Start at | Go-to baits |
|---|---|---|---|---|
| Spring | 3 to 25 ft | dawn & dusk | Pump Box Brook inflow (5 ft) | Stickbait off planer boards (shallow), Small spoon along mud lines |
| Summer | 25 to 60 ft | night & dawn | Break off the point (44 ft) | Spoon at the thermocline, Deep stickbait (night) |
| Fall | 5 to 30 ft | dusk & dawn | Pump Box Brook inflow (5 ft) | Jerkbait over gravel, Casting spoon |
| Winter | 5 to 35 ft | dawn | Pump Box Brook inflow (5 ft) | Jigging spoon, Small stickbait (slow) |
Spring chain pickerel on Mousam Lake hold shallow, usually 2 to 10 ft. They move out to 3 to 15 ft in summer and finish the year down in 5 to 18 ft. Put Back-bay flat first on the milk run — a weed flat near 5 ft that grades prime for spring. The feeding windows run early morning and the evening. The summer box starts with a weedless spoon + trailer or a buzzbait.
| Season | Depth | Best window | Start at | Go-to baits |
|---|---|---|---|---|
| Spring | 2 to 10 ft | midday & dawn | Back-bay flat (5 ft) | Inline spinner (silver), Small spoon (red/white) |
| Summer | 3 to 15 ft | dawn & dusk | Shallow bay flat (13 ft) | Weedless spoon + trailer, Buzzbait |
| Fall | 4 to 15 ft | midday & dawn | Shallow bay flat (13 ft) | Jerkbait along weed edges, Spinnerbait |
| Winter | 5 to 18 ft | dawn | Shallow bay flat (13 ft) | Jigging spoon (through ice) |
The spring pattern is a shallow one: lake trout in 10 to 40 ft. Midsummer fish sit out in 26 to 88 ft before dropping to 20 to 80 ft for winter. The spot to know is Deep basin, a deep basin in about 79 ft of water that rates prime for lake trout in summer. Plan around early morning in the warm months. Summer baits: a white tube jig (deep) or a magnum spoon on downrigger gets it done.
| Season | Depth | Best window | Start at | Go-to baits |
|---|---|---|---|---|
| Spring | 10 to 40 ft | dawn & dusk | Main-lake point (15 ft) | Casting spoon over shoals, Jerkbait (shallow) |
| Summer | 26 to 88 ft | dawn | Deep basin (79 ft) | White tube jig (deep), Magnum spoon on downrigger |
| Fall | 10 to 50 ft | dusk & dawn | Main-lake point (15 ft) | Heavy casting spoon, Jigging rap over reefs |
| Winter | 20 to 80 ft | dawn | Deep basin (79 ft) | White tube jig, Airplane jig |
Start shallow in spring: landlocked salmon sit in 1 to 15 ft that time of year. Summer pushes them deeper, 25 to 60 ft, and winter fish settle into 10 to 40 ft. The spot to know is Pump Box Brook inflow, an inflow / creek mouth in about 5 ft of water that rates prime for landlocked salmon in spring. Warm-month bites cluster around early morning and the evening. Throw a dodger + streamer down deep or a thin spoon on lead core until the fish tell you otherwise.
| Season | Depth | Best window | Start at | Go-to baits |
|---|---|---|---|---|
| Spring | 1 to 15 ft | dawn & dusk | Pump Box Brook inflow (5 ft) | Streamer flies (Grey Ghost) off boards, Thin spoon (Mooselook style) |
| Summer | 25 to 60 ft | dawn & dusk | Break off the point (44 ft) | Dodger + streamer down deep, Thin spoon on lead core |
| Fall | 5 to 30 ft | dawn & dusk | Pump Box Brook inflow (5 ft) | Casting spoon at the mouths, Streamers |
| Winter | 10 to 40 ft | dawn | Main-lake point (15 ft) | Small jigging spoon, Swedish pimple + smelt |
Mousam Lake also holds largemouth bass (8 to 20 ft in summer), smallmouth bass (10 to 30 ft in summer). Pick any of them on the map above for rated spots and bait picks.
The chart marks 11 structure features on Mousam Lake; the deepest is Deep basin at about 79 ft.
Access data: Maine GeoLibrary — Boat Launches (Maine IF&W / DACF). Confirm conditions and fees locally before you launch.
Season dates, license requirements, and size and bag limits for Maine waters are set by the Maine IFW — and special regulations can apply to Mousam Lake specifically, so confirm the current rules before you fish.
Check the official Maine fishing regulations →
Mousam Lake is about 88 ft (27 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 crappie, brook trout, brown trout, chain pickerel, lake trout, landlocked salmon, largemouth bass, smallmouth bass on Mousam Lake.
Pump Box Brook inflow is the top-rated area: an inflow / creek mouth in about 5 ft of water that rates prime for brook trout in spring. Open the map above to see every rated spot for each species and season.
For crappie, 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 Mousam Lake is regulated by the Maine IFW. Check the official Maine regulations for current license requirements, season dates, and size and bag limits — special regulations can apply to this specific water.
Square Pond 3 mi · Horn Pond 6 mi, NH/ME · Shaker Pond 7 mi · Lovell Lake 7 mi, NH · Great East Lake 7 mi, NH · Northeast Pond 8 mi, NH/ME · Balch Pond 8 mi, NH/ME · UNION MEADOWS 8 mi, NH · Townhouse Pond 9 mi, NH · Milton Pond 9 mi, NH/ME · Little Ossipee Lake 10 mi · Pine River Pond 11 mi, NH
See how Mousam Lake stacks up: best largemouth bass lakes in Maine · best smallmouth bass lakes in Maine · best crappie lakes in Maine · best lake trout lakes in Maine
More water nearby: York County fishing maps (7 charts). Browse all Maine fishing maps or 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.