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3,290-acre reservoir in Worcester County, Massachusetts. The lake tops out around 55 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.
On the chart, Sudbury Reservoir draws 3,287 acres inside 9.4 miles of shoreline — 3 islands included. Nearly circular (index 1.2), so the story is the bottom, not the bank. The shallow band under 15 ft claims about 73% of the surface — that's where the groceries are. End to end it runs roughly 3.2 mi, about 2.4 mi across. The water lies in Worcester County. For a second option, Hopkinton Reservoir lies 4 mi south.
The spring pattern is a shallow one: largemouth bass in 2 to 10 ft. As the season builds they drop to 8 to 20 ft, wintering in 15 to 35 ft. Top water on the chart: Weed flat, a weed flat in the 2 ft range, prime in spring. Time it for early morning and the evening. Summer baits: a texas-rigged 10" worm or a deep-diving crankbait gets it done.
| Season | Depth | Best window | Start at | Go-to baits |
|---|---|---|---|---|
| Spring | 2 to 10 ft | dawn & dusk | Weed flat (2 ft) | Spinnerbait, Chatterbait |
| Summer | 8 to 20 ft | dawn & dusk | Shallow feeding flat (13 ft) | Texas-rigged 10" worm, Deep-diving crankbait |
| Fall | 4 to 15 ft | midday & dawn | Shallow feeding flat (13 ft) | Squarebill crankbait (shad), Spinnerbait |
| Winter | 15 to 35 ft | midday | open water | Blade bait, Jigging spoon |
Start shallow in spring: smallmouth bass sit in 3 to 12 ft that time of year. Summer pushes them deeper, 10 to 30 ft, and winter fish settle into 20 to 45 ft. Warm-month bites cluster around early morning and the evening. Throw a drop shot (goby/minnow) or a ned rig until the fish tell you otherwise.
| 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 | open water | Drop shot (goby/minnow), Ned rig |
| Fall | 8 to 25 ft | midday & dawn | open water | Jerkbait, Blade bait |
| Winter | 20 to 45 ft | midday | open water | Blade bait, Hair jig |
Start shallow in spring: crappie sit in 2 to 8 ft that time of year. Summer pushes them deeper, 10 to 25 ft, and winter fish settle into 15 to 35 ft. The spot to know is Weed flat, a weed flat in about 2 ft of water that rates prime for crappie in spring. Warm-month bites cluster around early morning and the evening. Throw a jig trolled/spider-rigged or a small crankbait (trolled) until the fish tell you otherwise.
| Season | Depth | Best window | Start at | Go-to baits |
|---|---|---|---|---|
| Spring | 2 to 8 ft | midday & dawn | Weed flat (2 ft) | 1/16 oz jig + tube, Curly-tail grub |
| Summer | 10 to 25 ft | dawn & dusk | Shallow feeding flat (13 ft) | Jig trolled/spider-rigged, Small crankbait (trolled) |
| Fall | 8 to 20 ft | dawn | Shallow feeding flat (13 ft) | Jig + minnow combo, Small swimbait (1.5-2") |
| Winter | 15 to 35 ft | midday | Deep basin (55 ft) | Tungsten jig + soft plastic, Tiny jigging spoon |
In spring, bluegill run shallow here, mostly 1 to 6 ft. Summer pushes them deeper, 4 to 15 ft, and winter fish settle into 10 to 25 ft. Shallow bay flat is the standout, a weed flat at roughly 1 ft, rated prime for spring bluegill. Time it for early morning and the evening. You won't need more than a small sponge spider (fly) or a micro tube jig most summer days.
| Season | Depth | Best window | Start at | Go-to baits |
|---|---|---|---|---|
| Spring | 1 to 6 ft | midday & dusk | Shallow bay flat (1 ft) | 1/32 oz jig + micro plastic, Tiny popper (evenings) |
| Summer | 4 to 15 ft | dawn & dusk | Shallow feeding flat (13 ft) | Small sponge spider (fly), Micro tube jig |
| Fall | 6 to 18 ft | midday | Shallow feeding flat (13 ft) | Micro jig + waxworm, Small spoon tipped |
| Winter | 10 to 25 ft | midday | Shallow feeding flat (13 ft) | Tungsten ice jig + plastic, Tiny spoon |
Come spring, look for yellow perch tight to the bank in 3 to 12 ft. Expect a summer slide to 10 to 30 ft, then a winter hold in 15 to 35 ft. Start at Weed flat. It's a weed flat holding about 2 ft of water and rates prime come spring. Prime time lands in early morning. A drop-shot micro plastics or a small spoon tipped with worm is the honest summer answer here.
| Season | Depth | Best window | Start at | Go-to baits |
|---|---|---|---|---|
| Spring | 3 to 12 ft | midday & dawn | Weed flat (2 ft) | Small jig + curly tail, Perch-pattern micro crank |
| Summer | 10 to 30 ft | dawn | Shallow feeding flat (13 ft) | Drop-shot micro plastics, Small spoon tipped with worm |
| Fall | 12 to 35 ft | midday | Deep basin (55 ft) | Jigging spoon (small), Perch rig / spreader |
| Winter | 15 to 35 ft | midday & dawn | Deep basin (55 ft) | Tungsten jig + spikes, Rattle spoon (small) |
When the water first warms, chain pickerel slide up into 2 to 10 ft. By summer they slide out to 3 to 15 ft, and by winter most fish are in 5 to 18 ft. If you only fish one area, make it Weed flat: a weed flat around 2 ft that scores prime in spring. In summer the feeding windows fall in early morning and the evening. Keep a weedless spoon + trailer or a buzzbait rigged through the warm months.
| Season | Depth | Best window | Start at | Go-to baits |
|---|---|---|---|---|
| Spring | 2 to 10 ft | midday & dawn | Weed flat (2 ft) | Inline spinner (silver), Small spoon (red/white) |
| Summer | 3 to 15 ft | dawn & dusk | Weed flat (2 ft) | Weedless spoon + trailer, Buzzbait |
| Fall | 4 to 15 ft | midday & dawn | Shallow feeding flat (13 ft) | Jerkbait along weed edges, Spinnerbait |
| Winter | 5 to 18 ft | dawn | Shallow feeding flat (13 ft) | Jigging spoon (through ice) |
Sudbury Reservoir also holds white perch (15 to 40 ft in summer), pumpkinseed (2 to 10 ft in summer), brown bullhead (3 to 12 ft in summer). Pick any of them on the map above for rated spots and bait picks.
Structure-wise the chart holds 7 features, led in depth by Deep basin at roughly 55 ft.
Season dates, license requirements, and size and bag limits for Massachusetts waters are set by the MassWildlife — and special regulations can apply to Sudbury Reservoir specifically, so confirm the current rules before you fish.
Check the official Massachusetts fishing regulations →
Sudbury Reservoir is about 55 ft (17 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 largemouth bass, smallmouth bass, crappie, bluegill, yellow perch, chain pickerel, white perch, pumpkinseed, brown bullhead on Sudbury Reservoir.
Weed flat is the top-rated area: a weed flat in about 2 ft of water that rates prime for largemouth bass in spring. The interactive chart above rates every spot for each species and season.
For largemouth bass, 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 Sudbury Reservoir is regulated by the MassWildlife. Check the official Massachusetts regulations for current license requirements, season dates, and size and bag limits — special regulations can apply to this specific water.
Hopkinton Reservoir 4 mi · Chauncy Lake 5 mi · Farm Pond 5 mi · Little Chauncy Pond 5 mi · Bartlett Pond 5 mi · Ashland Reservoir 6 mi · Lake Boon 6 mi · Whitehall Reservoir 7 mi · Lake Cochituate North Basin 7 mi · A1 Site (Stump Pond) 7 mi · Lake Cochituate Midddle Basin 7 mi · Lake Cochituate South Basin 8 mi
See how Sudbury Reservoir stacks up: best largemouth bass lakes in Massachusetts · best smallmouth bass lakes in Massachusetts · best crappie lakes in Massachusetts · best bluegill lakes in Massachusetts
More water nearby: Worcester County fishing maps (73 charts). Browse all Massachusetts 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.